NOSTRAND'S  SCIENCE  SERIES. 

50  Cts. 

MODERN 

REPRODUCTIVE 

GRAPHIC  PROCESSES. 


JA8.  S.  PETTIT, 

First  Lit  iienant,  First  United  States  In f entry. 


/AN  NO  STRAND,  PUBLISHER, 
23  Murray  and  27  Warren  Street. 

1884 


C.  E.  Illustrated. 
No.  16. — A  GRAPHIC  METHOD  FOR  SOLVING 
CERTAIN  ALGEBRAICAL  EQUA- 
TIONS.   By  Prof.  George  L.  Yoi 
With  Illustrations. 


Date  Due 

trated. 


MODERN 

REPRODUCTIVE 

GRAPHIC  PROCESSES. 

BY  |        S  J  ' 

JAS.   S.  PETTIT, 

First  Lieutenant,  First  United  States  Infantry. 


NEW  YORK: 
D.  VAN  NO  STRAND,  PUBLISHER, 
23  Murray  and  27  Warren  Street. 
1884. 


Copyright,  D.  Van  Nostrand  1884. 


PREFACE. 


The  following  pages  were  prepared  for 
the  use  of  the  Department  of  Drawing 
of  the  U.  S.  Military  Academy,  as  a 
basis  for  elementary  instruction  in,  and 
with  a  view  to  the  imparting  of  some 
analytical  knowledge  of  the  means  em- 
ployed for  the  production  of  the  many 
beautiful  and  useful  prints,  &c,  that 
are  constantly  brought  before  the  pub- 
lic, either  in  the  publications  \)f  the 
day  or  in  more  artistic  shapes.  Each 
subject  could  be  expanded  into  a  separate 
volume.  Those  within  the  reach  of  ama- 
teurs, I  have  endeavored  to  explain  at 
length.  The  others  can  be  learned  only 
in  the  school  of  long  experience,  and 
text  books  would  be  of  little  assistance. 
I  am  indebted  to  the  courtesy  of  several 
publishing  firms  in  New  York,  and  to 
lit.  Lusk,  in  charge  of  the  laboratory  at 


iv 

Willet's  Point,  for  much  valuable  informa- 
tion, and  to  Messrs.  Abney,  Munckoven, 
Vidal,  Vogel  and  Griffin  for  the  use  of 
their  works  on  kindred  subjects. 

J.  S.  P. 


I  N  D  E  X . 


Albertype   82 

Applications  of  Photography   73 

Aquatint  e  „  114 

Autoglyph  78 

Autotype   78 

Autocopiste  Noir   13 

B. 

Blue  paper  process   9 

Bonnaudtype  123 

c. 

Carbon  prints   93 

Cerography    48 

Chromograph   12 

Chromo-lithography  43 

E 

Electrotypy  "   29 

Engraving   15 

Etching   26 

&. 

Gillotage  120 

H. 

Hektograph   12 

Heliogravure  110 

Heliotype   80 

Hoeschotype  ,  47 

L 

Indotint   78 


vi 


L. 

Lithography   35 

Luxotype  121 

M. 

Mezzotint    26 

o. 

Oleography   46 

P. 

Photography  53 

Wet  plate    56 

Dry  plate   62 

Instantaneous  ,  63 

Gelatine  bromide  of  silver   68 

Photogravure  , .  .105 

Gamier  109 

Photo-Lithography   40 

Photoglyph  103 

Phototype   87 

Photo-Zincography   91 

Polychrome  printing  122 

s. 

Sensitive  papers   8 

Similigravure  119 

Stannotype  (Woodbury)  104 

Stereotyping   33 

T. 

Transfer  97 

w. 

Woodcuts   16 

Woodbury  type  103 

z. 

Zincography   47 


PROCESSES  IN  USE  TO-DAY 


FOR  THE 

REPRODUCTION  OF  WORKS  OF  ART, 

Mechanical,  Engineering  and  Map  Drawings. 

Befoke  entering  into  a  detailed  de- 
scription of  the  various  processes  now  in 
use  in  the  reproduction  of  the  many 
beautiful  works  of  art,  maps,  mechanical 
drawings,  illustrations,  &c,  it  might  be 
well  to  state  that,  due  to  the  constantly 
increasing  number  of  discoveries  in  the 
sciences  of  optics  and  chemistry,  the 
great  rivalry  between  large  publishing 
houses,  the  diffusion  of  knowledge  on 
art,  and  the  increased  appreciation  of 
artistic  things,  many  of  the  methods 
herein  described  are  undergoing  changes 
and  improvements  in  the  details,  with  in- 
creasing ranges  in  application.  This  is 
especially  true  of  the  various  ap  plica- 


8 


tions  of  photography.  Good  paintings, 
engravings  and  etchings,  and  fine  photo- 
graphs will  always  be  appreciated  by  ed- 
ucated people.  The  various  patented 
processes  must  fluctuate  with  a  very  un- 
certain popular  taste. 

I  find  the  following  to  be  the  practical 
processes  of  the  present  day  : 

1.  Sensitive  paper  processes. 

2.  Hektograph. 
.  3.  Engraving. 

4.  Electrotypy. 
5*  Lithography. 

6.  Photography. 

7.  Miscellaneous. 

Mention  must  be  made  of  the  fact 
that  many  of  the  fine  works  of  the  old 
masters  are  frequently  copied,  not  only 
by  artists  desirous  of  studying  them, 
but  by  others  for  pecuniary  purposes, 
and  so  skillfully  is  this  done  that  the 
judgment  of  experts  will  sometimes  fail 
to  distinguish  them  from  the  originals, 
for  which  they  are  falsely  sold. 

Sensitive  Papers. — The  process  in  gen- 


9 


eral  use  to-day  in  large  manufacturing 
establishments,  architects'  offices,  &c,  is 
ordinarily  known  as  the  "  blue  paper " 
process,  so-called  because  the  sensitized 
surface  turns  from  a  dark  grey  to  a  blue 
color  on  exposure  to  the  light  and  after 
washing.  The  drawing  to  be  copied 
must  be  made  on  good,  clear  tracing 
paper,  and  with  a  very  heavy  opaque  ink. 
It  is  then  placed  on  a  frame,  on  top  of 
the  sensitized  paper,  the  frame  having  a 
heavy  glass  lid,  which  should  press  even- 
ly on  the  surface  of  the  drawing  and 
hold  it  firmly  down  to  the  paper.  It  is 
then  exposed  to  the  light  for  fifteen  or 
twenty  minutes.  After  sufficient  expo- 
sure the  sensitive  paper  is  washed  in  a 
clean  water  bath.  The  parts  affected  by 
the  light  have  become  insoluble,  while 
the  parts  screened  by  the  interposition 
of  the  lines  wash  out,  leaving  the  clear 
white  of  the  paper  on  a  back-ground  of 
blue. 

The  following  formula  is  used  in 
the  laboratory  at  Willett's  Point  with 
most  excellent  results : 


10 


Double  citrate  of  iron  and  ammonia  loz. ) 


For  use,  mix  equal  quantities  and  float 
paper  for  two  minutes.  The  mixture  is 
poured  into  a  flat  dish.  The  paper  is 
then  taken  by  diagonally  opposite  cor- 
ners, giving  it  a  convex  surface.  This 
convex  surface  is  gently  placed  in  con- 
tact with  the  surface  of  the  liquid ;  the 
corners  are  then  dropped  and  the  paper 
floats  on  the  surface.  The  corners  must 
be  carefully  lifted  in  a  few  seconds,  and 
the  air  bubbles  on  the  surface  of  the 
paper  must  be  removed  with  a  brush. 
After  floating,  the  paper  is  placed  in  a 
dark  place  to  dry,  and  must  be  rolled  up 
and  kept  from  the  light  until  ready  for 
use. 

The  following  process  will  give  black 
lines  on  a  white  ground.  The  paper  is 
coated  with  the  sensitive  solution  by 
drawing  it  in  continuous  bands  over  a 
roller  saturated  with 


Water. 


4oz.  j" 


Red  prussiate  of  potassium 
Water. 


11 


Sulphate  of  iron 
Chlorate  "  " 

Gelatine  

Tartaric  acid. . . 
Dist.  water  


10  grammes. 


20  c.  c. 


10  " 

300  " 


10  grammes. 


It  must  then  be  hung  up  to  dry,  pro- 
tected from  the  light  and  air.  The  draw- 
ing is  made  on  tracing  paper  with  a  deep 
black  ink.  The  exposure  is  made  as  in 
the  "blue"  process,  and  must  be  con- 
tinued until  the  ground  is  seen  to  turn 
white.  It  is  then  removed  from  the 
frame  and  immersed  in  the  following 
solution : 

200  grammes  gallic  acid, 
20        "  alcohol, 
1,000    "  water. 

It  is  then  washed  in  water  and  dried.  It 
is  much  more  difficult  to  handle,  and 
more  expensive  than  the  blue  process, 
and  is  seldom  used. 

I  have  been  told  the  Major  Jones,  of 
the  Corps  of  Engineers,  obtained  most 
excellent  copies  of  the  original  drawing 
by  using  the  following  method.  The 


12 


drawing  was  first  made  on  tracing  paper 
with  a  mucilaginous  ink.  This  was 
transferred  by  the  above-mentioned  proc- 
ess to  a  paper  which  was  sensitized  with 
the  silver  solution,  giving  the  drawing  in 
white  lines  on  a  black  surface.  This  copy 
was  in  turn  placed  over  the  same  kind 
of  paper,  and  after  exposure  and  wash- 
ing he  got  excellent  reproductions  of  the 
original — black  lines  on  white  paper.  I 
have  seen  some  maps  and  many  machine 
drawings  made  by  the  "  blue  "  process. 
They  were  very  good,  and  suited  to  the 
purposes  for  which  they  were  made.  Of 
course  this  process  would  be  too  slow 
where  a  great  number  of  copies  is  de- 
sired. Blue  lines  on  a  white  ground 
give  the  most  pleasing  effect. 

Hektograph,  or  Chromograph  (French). 
— This  is  an  exceedingly  useful  and  a 
very  simple  little  arrangement  of  gela- 
tine for  reproducing  letters,  manuscripts 
and  small  drawings  which  do  not  require 
great  accuracy  or  much  elegance.  It  is 
based  on  the  discovery  that  gelatine 
forms  an  excellent  body  for  receiving  and 


13 


holding  certain  aniline  inks.  The  draw- 
ing is  first  made  on  paper  with  hekto- 
graph  ink,  and  is  transferred  to  the  gela- 
tine by  simply  pressing  the  drawing  on 
the  surface.  If  printed,  while  the  ink  is 
fresh,  one  good  impression  will  admit  of 
as  high  as  fifty  copies  in  fair  condition. 
The  violet  ink  seems  to  be  the  best  and 
brightest.  After  the  printing  is  com- 
pleted the  surface  of  the  gelatine  must 
be  washed  off  with  a  sponge  and  clean 
water.  This  is  quite  troublesome.  The 
gelatine  solution  can  be  poured  into  a 
glass  jar.  When  ready  to  print  put  the 
jar  into  hot  water,  and  allow  it  to  stand 
until  the  gelatine  will  flow.  Pour  a  film 
on  a  glass  plate  as  a  photographer  pours 
collodion.  Allow  this  to  set,  and  it  is 
ready  for  use  as  prescribed  for  the  hek- 
tograph.  When  through,  heat  the  plate 
and  wipe  off  the  gelatine. 

Autocopiste  Nora. — In  order  to  avoid 
the  use  of  aniline  inks,  which  are  very 
unstable,  M.  Lelm  invented  another 
process,  called  "autocopiste  noir."  It  is 
very  similar  to  Hektography  in  operation. 


14 


He  makes  use  of  a  special  ink,  composed 
of  a  solution  of  the  perchloride  of  iron 
and  water,  with  coloring  water  added  to 
enable  the  operator  to  see  the  lines  he 
traces.  The  vehicle  to  which  the  trans- 
fer is  made  consists  of  gelatine,  to  which 
a  little  alum  is  added  to  harden  the  film., 
This  is  spread  evenly  on  strong  parch- 
ment paper.  The  drawing  is  placed  face 
down  on  this,  and  is  transferred  to  the 
gelatine  by  hand  pressure,  as  in  the  Hex- 
tograph.  After  removing  the  original,  a 
roller,  covered  with  the  prepared  ink, 
which  comes  in  tubes,  is  passed  quickly 
over  the  film,  as  in  lithography.  The 
ink  adheres  only  to  the  lines ;  press  the 
paper  which  is  to  receive  the  copy,  on 
the  film,  with  the  hand,  and  then  re- 
move it  carefully ;  re-ink  the  film  and 
another  copy  can  be  taken.  The  pre- 
pared parchment  is  placed  in  a  case  which 
keeps  it  stretched.  Before  applying  the 
original  drawing  to  the  gelatine  the  roll- 
er full  of  ink  must  be  passed  from  one 
end  to  the  other  of  the  parchment  sheet. 
If  it  takes  any  of  the  ink  the  entire 


15 


sheet  must  be  wiped  off  with  a  damp 
sponge,  and  be  thoroughly  cleaned  and 
dried.  These  prints  have  all  the  dura- 
bility of  prints  with  a  carbon  base.  The 
prepared  parchment  is  put  in  a  stretching 
case,  and  can  be  purchased  ready  for 
use. 

Engraving. — To  engrave  has  but  one 
signification,  viz.,  that  of  marking  by 
incision.  The  rudest  mark,  if  it  is  cut 
into  the  substance,  is  engraving.  Some 
of  the  applications  of  photography,  such 
as  the  Heliogravure  and  Photogravure, 
are  engraving,  for  the  surface  of  the 
plate  is  cut  away  by  the  action  of  acids. 
Etching  is  also  included  under  the  gen- 
eric name  of  engraving,  but  has  a  tech- 
nical signification  of  its  own. 

Engraving  is  older  than  printing,  and 
dates  from  the  first  quarter  of  the  15th 
century.  Wood  engraving  was  learned 
from  the  Chinese.  The  process  of  print- 
ing from  metal  plates  was  not  discov- 
ered until  towards  the  close  of  the  15th 
century.  Its  history  from  that  day  to 
this  is  exceedingly  interesting.    It  has 


16 


always  been  subordinate  to  painting,  but 
some  original  work  has  been  executed  by 
good  engravers.  The  apprenticeship  to 
the  art  is  necessarily  long  and  tedious. 

The  chased  ornamentation  of  watches, 
silver-plate,  &c,  is  engraving.  I  shall 
confine  myself,  however,  to  its  technical 
signification  as  one  of  the  fine  arts.  The 
following  are  the  usual  varieties  of  en- 
graving : 

1.  Pure  line  engraving*  on  metal  plates, 
usually  of  copper  or  steel. 

2.  Mezzotint. 

3.  Wood-cuts  :  in  which  the  lines  that 
print  black  must  be  left  in  relief. 

In  chronological  order  the  wood-cut 
comes  first.  The  genius  of  steel  engrav- 
ing has  not  improved  since  the  days  of 
Diirer  and  Marcantonio  notwithstand- 
ing the  progress  in  means  and  materials. 
Wood  engraving  has,  in  the  past  thirty 
years,  grown  into  a  wonderful  degree  of 
excellence,  and  has  widened  into  a  range 
of  application  that  covers  almost  all  de- 
grees of  artistic  reproduction.  As  a 
"process"  it  is  not  surpassed  by  any 


17 


known  invention,  unless,  perhaps,  it  be 
the  Photogravure  process,  as  executed  by 
Messrs.  Goupil  &  Co.,  in  Paris.  Some 
writers  go  so  far  as  to  claim  that  there 
is  nothing  artistic  which  can  not  be  ex- 
actly reproduced  on  wood.  The  best  of 
our  wood  engravers  are,  beyond  dispute, 
the  best  in  the  world,  and  the  beautiful 
prints  published  in  our  standard  maga- 
zines have  never  been  equaled  in  any 
country  at  any  time.  We  may  well  feel 
proud  of  the  progress  of  our  country- 
men in  this  art,  and  a  little  time  will  do 
much  for  us  in  the  others.  It  is  difficult 
to  believe  that  the  work  done  by  Cole, 
Miiller,  Juengling  and  others  can  ever 
be  excelled,  and  yet  we  cannot  believe 
that  perfection  has  been  reached.  The 
wood  engraving  of  to-day  has  made  no 
advance  in  principle  over  that  of  Diirer 
and  Thomas  Bewick.  It  fills  a  different 
sphere,  and  has  been  greatly  assisted  in 
the  results  of  its  practice  to-day  by  the 
use  of  modern  presses,  paper,  ink,  photog- 
raphy, and  electrotypy,  though  many  of 
our  best  engravers  prefer  to  work  from 


18 


a  drawing  on  the  block  rather  than 
from  a  photograh. 

Photographs  of  paintings,  engravings, 
&c.,  have  frequently  to  be  much  reduced 
in  size,  and  it  is  very  difficult  to  work 
out  an  exact  copy  of  the  original. 
Again,  red  and  yellow  colors  in  a  paint- 
ing take  dark,  and  blue  and  violet  take 
white  in  a  photograph,  so  that  it  is  nec- 
essary for  an  engraver  to  have  the  origi- 
nal by  him  for  reference  in  order  to  give 
expression  to  the  true  color  value  of  the 
painting.  The  history  of  engraving  is 
long,  but  exceedingly  interesting,  and  I 
must  refer  the  student  to  other  works 
written  on  this  subject  alone,  as  it  is 
scarcely  within  the  province  of  this 
article  to  give  more  than  a  description  of 
the  mechanical  and  artistic  means  em- 
ployed for  the  production  of  finished 
work. 

We  may  divide  the  process  into  five 
distinct  operations,  viz.  :  1.  The  drawing 
or  photographing  of  the  picture  on  the 
block  ;  2,  the  engraving ;  3,  the  mould- 
ing in  wax ;  4,  the  electrotyping  of  the 


19 


mould ;  5,  the  setting  and  printing. 
Each  operation  requires  special  care,  and 
the  fineness  of  the  original  is  a  little 
blunted  by  each  operation.  The  artist's 
proofs,  obtained  by  methods  of  his  own, 
and  with  much  time  and  care  devoted  to 
printing,  are  much  superior  to  the  copies 
obtained  from  a  powerful  and  rapid 
press,  printing  hundreds  of  copies  in  one 
hour. 

(1.)  The  Preparation  of  the  Block. 
— A  block  of  boxwood  of  unifrom  thick- 
ness, and  cut  across  the  grain,  is  care- 
fully polished  and  cleaned,  and  is  cov- 
ered with  a  light  coating  of  Chinese 
white,  giving  a  grey  tint  to  the  block. 
The  drawing  is  made  on  this,  either  by 
the  artist  or  by  the  engraver,  or  by  the 
photographer,  as  the  case  may  be.  There 
are  but  few  photographers  competent  to 
do  this  work  without  filling  the  block 
with  silver,  which  interferes  with  the  cut- 
ting. (2.)  Engraving. — This,  of  course, 
is  the  main  feature  of  the  work,  and  to 
it  the  engraver  must  bring  his  artistic 
skill  and  genius,  coupled  with  his  own 


20 


particular  method  of  working.  If  he  be 
a  true  engraver  his  endeavor  will  be  to 
thoroughly  translate  the  genius  and 
ideas  of  the  artist  whose  work  he  is  en- 
deavoring to  place  before  the  public. 
Herein  lies  the  difficulty.  Ihe  lights  of 
the  drawing  must  be  cut  out  so  as  to 
leave  the  darks,  from  which  the  print  is 
to  be  taken,  in  clear,  distinct  relief. 

In  this,  wood  engraving  is  more  diffi- 
cult than  its  more  aristocratic  counter- 
part, steel  engraving.  In  the  latter  the 
cross  hatchings  can  be  readily  made  with 
the  burin  without  any  trouble  as  to  what 
will  be  left  in  relief,  but  the  wood  en- 
graver must  cut  out  each  little  diamond- 
shaped  space  between  the  lines,  and 
leave  the  edges  clean  and  sharp.  Again, 
if  he  desires  to  copy  an  engraving  faith- 
fully, the  little  dots  often  placed  in  the 
diamond-shaped  spaces  by  engravers  on 
metal  must  be  cut  around  and  left.  Such 
skill,  however,  has  been  reached  by  our 
good  engravers  that  they  can  faithfully 
represent  crayon  or  pencil  drawings,  line 


21 


engravings,  etchings,  and  even  the  brush 
mark  on  paintings. 

After  the  engraving  is  finished  and  the 
block  cleaned,  a  proof  is  taken ;  if  satis- 
factory a  wax  mould  of  the  block  is 
made.  This  is  black-leaded,  and  electro- 
typed  in  copper,  as  will  be  described, 
and  after  being  backed  with  type  metal 
and  "type  high"  wood,  it  is  ready  for 
the  printer.  The  fine  prints  executed  by 
the  Century  Co.  and  Harper  Bros,  are 
obtained  with  much  labor  and  care. 
Cylinder  presses  with  several  inking 
rollers  are  used ;  but  one  side  of  the 
paper  is  printed  at  a  time,  and  dry  paper 
is  used.  A  light  pressure  proof  is  taken 
first,  and  an  examination  of  this  shows 
whether  any  parts  of  the  form  are  too 
high  or  too  low.  The  low  parts  are 
raised  up  by  underlaying  the  block  with 
bits  of  paper  until  the  desired  height  is 
obtained.  As  all  printing  machines  are 
made  to  give  an  even  impression  on  all 
parts  of  the  "form,"  cuts  with  strong 
contrasts  of  light  and  shade  must  be  so 
arranged  as  to  receive  different  degrees 


22 


of  pressure,  which  should  be  very  strong 
on  the  intense  blacks,  firm  on  the 
middle  tints,  and  light  on  the  others. 
This  is  obtained  by  the  process  of  "  over- 
laying." The  pressman  first  prints  a 
number  of  flat  proofs  on  different  thick- 
nesses of  paper.  The  "overlayer"  cutter 
compares  these  with  the  artist's  proofs,  and 
decides  how  many  overlays  he  will  need 
to  produce  the  work  to  advantage.  If 
he  decides  to  use  three  overlays  he  cuts 
out  of  the  proofs,  skeleton  figures  of  the 
strong  blacks,  of  the  middle  tints,  and  of 
the  lightest  tones.  He  puts  these  accu- 
rately on  the  cylinder  so  that  the  strong 
blacks  shall  have  three,  the  middle  tints 
two,  and  the  light  grays  one  thickness  of 
paper  to  increase  the  pressure  on  the 
corresponding  parts  of  the  electrotype, 
and  these  overlays  must  be  attached  to 
the  cylinder  and  to  each  other,  so  that 
they  will  cover  exactly  the  corresponding 
lines  on  the  electrotypes.  This  work  is 
necessarily  long  and  tedious,  but  the 
beauty  of  the  results  amply  repays  for 
the  time  and  care  expended. 


23 


Many  prints  are  made  directly  from 
the  wooden  block,  but  only  coarse  blocks 
can  be  used  for  a  large  number  of  copies, 
as  printing  in  the  rapid  and  powerful 
steam  presses  of  to-day  would  soon  blunt 
the  sharp  lines  of  the  drawing  and  make 
the  block  utterly  useless.  It  is  impos- 
sible to  obtain  the  pure,  clean  lines  of 
an  engraving  in  metal,  from  a  relief  plate. 
In  the  latter,  the  prints  are  merely  dark- 
ened surfaces,  and  the  ink  must  of  neces- 
sity spread  a  little,  while  from  the  former 
we  get  a  black  cast  of  the  line,  with 
sharp,  clean  edges.  Large  wood  cuts 
are  frequently  divided  into  sections,  and 
executed  by  separate  engravers.  The 
blocks  are  then  joined  together  and  elec- 
trotyped  as  described  above.  We  can 
readily  see  that  the  engravers  must  work 
so  as  to  give  similar  tones  to  the  differ- 
ent parts.  What  the  future  of  wood  en- 
graving will  be  can  only  be  a  matter  of 
conjecture.  It  is  at  present  passing 
through  an  era  of  favor  and  success 

Line  Engkaving  on  Metal. — The  man- 
ner of  printing  from  an  engraved  metal 


24 


plate  is  the  converse  of  that  used  in  ob- 
taining a  print  from  a  wood  cut.  In  the 
latter  it  is  the  raised  parts,  in  the  former 
it  is  the  parts  cut  out  which  give  the 
darks  of  the  picture.  The  metal  plate 
must  be  carefully  made  of  a  uniform 
thickness  throughout,  and  the  surface  to 
be  engraved  must  be  carefully  polished 
and  cleaned.  It  must  be  free  from  blenv 
ishes  of  all  kinds,  as  the  slightest  scratch 
on  the  metal  will  show  on  the  print.  The 
lines  are  cut  with  a  little  steel  instru- 
ment called  a  burin,  which  is  simply  a 
small  hand  tool,  with  a  (Q)  diamond 
shaped  edge,  and  which  the  engraver 
holds  between  the  thumb  and  forefinger 
and  pushes  from  him  instead  of  drawing 
towards  the  body,  as  we  would  a  pen  or 
pencil.  By  varying  the  pressure  the 
lines  are  made  deeper  or  more  shallow  at 
the  pleasure  of  the  engraver,  and  the  re- 
sult depends  solely  upon  his  genius  and 
skill.  Much  of  the  engraving  of  to-day 
is  done  with  machinery.  The  broad  sur- 
faces of  skies,  foregrounds,  etc.,  are 
readily  and  beautifully  done  in  this  way. 


25 


The  plates  are  cut  while  soft,  and  are 
tempered  before  printing.  The  plate 
is  covered  with  ink,  either  with  a  roller  or 
a  dabber.  The  surface  is  carefully  wiped 
off,  first  lightly  with  a  cloth,  and 
then  with  the  palm  of  the  hand.  The 
paper  is  slightly  moistened,  and  the 
pressure  of  the  press  forces  it  into  the 
incisions  in  the  plate,  from  which  it  ab- 
sorbs the  ink. 

The  ink  from  the  markings  settles  on 
the  paper  in  strong,  distinct  lines,  and 
the  darks  are  much  purer  and  stronger 
than  in  a  wood  cut.  In  block  printing 
the  line  is  only  a  blackened  surface,  in 
plate  printing  it  is  a  cast.  The  line  may 
be  of  exceeding  fineness,  it  will  print  just 
the  same.  The  art  of  line  engraving 
seems  to  be  doomed  to  extinction.  There 
are  still  a  few  good  engravers  in  the 
world,  but  engravings,  if  good,  are  ex- 
pensive, and,  worse  than  that,  their  place 
in  public  and  popular  estimation  has 
been  usurped  by  the  cheaper  productions 
of  the  etcher,  and  the  many  excellent  pa- 
tented processes  based  on  photography. 


26 


Mezzotint. — For  the  Mezzotint  the 
surface  of  the  plate  is  first  worked  over 
in  many  directions  with  a  small  tool 
called  a  cradle,  which  is  a  chisel-shaped 
instrument  with  a  circular  edge,  having 
many  fine  teeth.  This  gives  the  surface 
a  fine  grain,  with  many  little  projections. 
The  parts  are  then  cut  away  with  a  sharp 
instrument  called  a  scraper,  and  at  the 
pleasure  of  the  engraver.  The  parts 
which  are  to  print  white  are  entirely  cut 
away  and  the  surface  burnished.  This 
process  is  better  adapted  to  the  expression 
of  texture  in  garments,  clouds,  &c,  than 
the  pure  line  engraving,  but  the  beauti- 
ful effects  and  expressions  of  the  line 
are  omitted.  It  is  quite  common  to  see 
the  two  combined  in  the  same  plate.  The 
burin  being  used  where  it  can  be  made 
most  effective.  Mezzotint  plates  are, 
unfortunately,  not  very  durable,  and 
after  a  few  hundred  copies  have  been 
taken,  the  little  projections  become 
blunted  and  the  effects  destroyed. 

Etching. — Etching  is  a  species  of  en- 
graving in  which  the  cutting  is  done  by 


27 


the  action  of  an  acid.  Pen  sketches  are 
very  frequently  and  very  improperly 
called  etchings.  Etchings  are  very  pop- 
ular to-day,  and  are  very  handsomely  ex- 
ecuted. The  process  is  substantially  as 
follows:  To  prepare  the  plate,  it  must 
first  be  covered  with  an  etching  ground, 
a  composition  that  will  resist  acid,  and  it 
must  be  so  adhesive  that  it  will  not  quit 
the  metal  when  fine  strips  are  left  iso- 
lated between  lines,  and  yet  it  must  be 
easily  removed  by  the  etching  point. 
The  following  mixture  is  found  to  give 
an  excellent  body :  Melt  two  ounces  of 
white  wax,  add  one  ounce  of  gum  mastic 
in  powder,  a  little  at  a  time,  stirring  un- 
til they  are  well  mingled,  then  add  in  the 
same  manner  an  ounce  of  bitumen  in 
powder.  To  apply  the  ground  to  the 
plate  the  composition  is  melted,  and  a 
little  of  the  essential  oil  of  lavender  is 
added.  When  the  mixture  is  cool  it 
forms  a  thin  paste,  which  is  applied  to 
the  plate  with  a  small  hand  roller.  The 
surface  is  then  smoked  by  holding  the 
plate  over  the  flame  of  a  candle  or  tallow 


28 


dip ;  the  drawing  is  made  on  this,  and 
the  composition  is  removed  from  the 
parts  to  be  etched,  by  means  of  an  etcher's 
point ;  the  acid  is  then  applied,  and  the 
depth  to  which  the  eating  is  allowed  to 
proceed  is  left  to  the  skill  and  desire  of 
the  etcher,  as  the  biting  may  be  stopped 
out  at  any  point  very  readily  by  remov- 
ing the  acid.  After  the  biting  in  is  fin- 
ished and  the  composition  removed  the 
burin  may  be  used  in  finishing  up  parts 
found  to  be  insufficiently  etched.  The 
plate  is  printed  from  in  the  same  manner 
as  the  engraved  plate,  and  gives  beautiful 
and  very  artistic  results. 

Copper  is  the  best  substance  to  etch 
and  engrave  upon ;  steel  resists  printing 
better,  but  is  not  nearly  so  agreeable  to 
work  upon,  and  does  not  yield  such 
beautiful  prints.  Etching  is  the  only 
form  of  engraving  that  has  ever  been 
practiced  directly  from  nature.  Etchers 
go  out  with  their  materials  like  painters 
or  any  other  draughtsmen.  Dry  point 
is  often  used  in  connection  with  etch- 
ing.   The  lines  are  scratched  on  the 


29 


polished  surface  with  a  sharp  steel  point. 
Etching  is  extremely  favorable  to  the 
imitation  of  textures  such  as  the  intricacy 
of  lace  work,  the  richness  of  velvet,  the 
sheen  of  armour. 

ElecteotypYo — The  ordinary  form  of  a 
Daniell  cell  is  a  copper  vessel  containing  a 
saturated  solution  of  blue  vitriol  (sulphate 
of  copper),  inside  of  which  is  placed  a 
porous  jar  containing  dilute  sulphuric  acid. 
If  a  rod  or  strip  of  zinc  be  placed  in  the 
acid  and  be  connected  with  the  copper 
vessel  by  a  wire,  electrical  action  will 
immediately  take  place.  The  zinc  plate 
will  be  gradually  decomposed  with  a 
consequent  formation  of  zinc  sulphate  in 
the  porous  cell,  and  pure  copper  will  be 
disengaged  from  the  sulphate,  and  will 
be  found  deposited  on  the  surface  of  the 
copper  vessel,  the  current  passing  from 
the  positive  generating  zinc  plate  to  the 
negative  copper  pole.  By  the  use  of  a 
copper  coin  in  some  of  the  early  experi- 
ments with  electricity,  it  was  discovered 
that  a  very  perfect  copy  of  the  coin  was 
formed^  with  the  exception,  of  course,, 


30 

that  the  copy  was  in  intaglio;  a  bit  of  var- 
nish was  accidentally  dropped  on  the  sur- 
face of  the  coin  and  no  deposition  of 
metal  was  found  over  the  varnish,  which 
was  a  non-conductor,  and  the  operator 
saw  that  he  had  the  power  of  directing 
the  deposition  at  his  pleasure  The  ap- 
paratus was  for  many  years  very  rude. 
The  strength  of  the  copper  solution  had 
to  be  maintained  by  the  addition  of  crys- 
tals of  the  salt,  and  the  zinc  plates,  which 
were  quickly  eaten  away,  had  to  be  re- 
newed. For  carrying  on  the  operation 
extensively,  a  large  number  of  cells  was 
necessary,  and  this  method  was  replaced 
by  the  use  of  dynamo  electric,  or  mag- 
neto-machines. If  a  coil  of  copper  wire 
be  revolved  between  the  poles  of  an 
electro-magnet,  a  current  of  electricity 
will  be  generated  in  the  wire  at  each 
half  revolution ;  in  the  next  half  revo- 
lution, a  similar  current  will  be  gen- 
erated, but  in  the  opposite  direction. 
By  means  of  a  little  instrument  called 
a  commutator,  these  counter  cur- 
rents  are  converted  into  a  constant 


31 


stream  of  electricity,  and  this  current  is 
utilized  in  the  electrolysis.  Large  and 
powerful  machines  are  constructed,  run 
by  steam-power.  It  is  said  that  there  is 
one  at  Birmingham  which  will  deposit 
4^  cwt.  of  copper  in  24  hours.  Wood  en- 
gravings may  be  eiectrotyped  by  coating 
the  surface  with  a  wash  of  black  lead  and 
then  placing  the  block  in  the  current  by 
a  connecting  wire.  The  finest  scratches 
and  the  smallest  ridges  are  faithfully  re- 
produced. To  obtain  an  exact  copy  of 
the  object,  the  matrix  or  first  plate  is  in 
turn  eiectrotyped.  The  surface  to  be 
eiectrotyped  must  be  perfectly  free  from 
stains  and  grease  spots.  The  electro- 
typing  of  objects  of  the  most  delicate 
nature,  such  as  Daguerreotypes  and 
negatives  (which  are  metallic),  is  now 
done  with  perfect  ease.  Insects,  flowers, 
etc.,  may  be  faithfully  reproduced  by 
first  immersing  them  in  a  metallic  so- 
lution. 

The  process  of  electrotyping  is  simple 
and  moderately  expensive.  It  is  used 
extensively  in  the  engraving  department 


32 


of  the  Coast  Survey  office,  with  apparatus 
that  will  cause  the  deposit  of  from  two  to 
three  lbs.  of  copper  per  square  foot  in 
24  hours.  The  copy,  after  removal  from 
the  mould,  is  strengthened  by  a  backing 
of  type  metal,  and  is  then  ready  for  the 
press.  It  is  admirably  adapted  to  map 
work,  which  is  generally  pure  line-work. 
It  is  also  the  final  step  in  many  of  the 
processes  based  on  photography,  both  for 
the  production  of  engraved  plates  and 
plates  in  high  relief.  The  copper  is  sup- 
plied by  putting  a  plate  of  the  pure  metal 
in  the  current  in  front  of,  and  parallel  to 
the  surface  to  be  electrotyped.  Electro- 
plating is  similar  to  electrotyping,  except, 
of  course,  the  deposit  remains  on  the 
metal,  and  forms  an  inseparable  part  of 
the  object.  Many  small  objects  can  be 
electrotyped  or  electroplated  in  the  same 
bath  at  the  same  time  by  simply  attach- 
ing them  to  the  proper  pole  of  battery. 
For  depositing  copper,  a  solution  of  the 
sulphate  is  used ;  for  silver  a  solution  of 
cyanide  of  silver,  in  cyanide  of  jDotassium ; 
for  gold,  the  double  cyanide  of  gold  and 


(INSTITUTE 

potassium.  It  must  be  borne  in  mind 
that  the  cyanide  of  potassium  is  a  rank 
poison. 

Stereotyping. — The  process  of  stereo- 
typing a  valuable  work,  for  the  purpose  of 
saving  it  for  subsequent  editions,  is  now 
a  very  simple  proceeding.  In  its  early 
stages  of  development  a  plaster  cast  of 
the  type  form  was  taken,  and  this  was  in 
turn  put  through  a  troublesome  process 
in  order  to  obtain  a  metallic  mould  of  the 
plaster ;  defective  parts  had  to  be  taken 
out  and  new  letters  or  words  set  into  the 
metal,  and  in  addition  to  this  the  enor- 
mous quantity  of  metal  necessary  to 
stereotype  a  large  work,  made  handling 
and  storage  quite  important  features. 
Electrotypy  has  completely  changed  this 
laborious  process  into  one  of  easy  manip- 
ulation, and  certainly  of  good  results. 
A  sheet  of  wax,  covered  with  a  coating 
of  graphite,  is  laid  upon  the  type  form, 
and  is  secured  in  a  shallow  pan  called 
the  moulding  pan.  Strong  pressure 
forces  the  wax  into  all  the  interstices, 
and  even  into  the  lines  of  the  wood  cuts. 


34 


The  moulding  pan  is  then  removed,  and 
the  impression  is  covered  with  a  second 
coating  of  black  lead,  and  is  then  placed 
in  the  electric  circuit,  and  regularly  elec- 
trotyped  and  backed.  Mr.  Silas  P.  Knight, 
of  New  York,  pours  a  solution  of  the  sul- 
phate of  copper  over  the  graphite,  and 
then  dusts  on  this  fine  iron  filings.  De- 
composition and  recomposition  take  place 
immediately.  The  acid  leaves  the  cop- 
per and  unites  with  the  iron,  depositing 
a  coating  of  pure  copper  on  the  mould, 
it  is  then  placed  on  the  circuit  and  kept 
there  until  the  thickness  of  the  deposi- 
tion is  about  that  of  blotting-paper.  It 
must  now  be  backed  with  strong  metal, 
as  printing  would  crush  the  mold  out  of 
shape. 

The  shell  is  placed  face  down,  and  the 
back  is  washed  with  a  solution  of  chloride 
of  tin  to  make  the  metal  adhere.  A 
sheet  of  tin-foil  is  laid  on  this,  and  the 
pan  is  heated  to  about  460,°  when  the 
tin  melts.  Melted  metal  is  now  poured 
into  the  mould  and  a  solid  plate  is  formed. 
This  plate  is  trimmed  and  made  of  the 


35 


proper  thickness,  and  is  stowed  away  for 
future  use.  Electrotypy  does  not  cost  more 
than  the  stereotype,  it  will  wear  much 
longer,  and  gives  far  more  perfect  im- 
pressions, as  electrotypes  are  practically 
as  good  as  the  original  blocks  from  which 
they  were  taken 


Lithography  •<  Photo-Lithography, 


In  lithography  we  have  one  of  the 
simplest  and  yet  the  most  useful  and 
most  extensive  of  the  industrial  arts.  It 
is  based  on  the  antagonistic  qualities  of 
grease  and  water.  The  greasy  litho- 
graphic ink  is  made  to  adhere  to  a 
polished  surface  of  a  peculiar  kind  of 
limestone  obtained  in  Bavaria.  The  parts 
thus  covered  acquire  the  property  of  re- 
ceiving printer's  ink,  which  is  prevented 
from  adhering  to  the  other  parts  by  the 
interposition  of  the  water. 

The  lithographic  stone  is  a  very  fine- 
grained homogeneous  limestone,  and  is 
imported  free  of  duty.  It  is  cut  into 
blocks  of  from  two  to  three  inches  in 


Lithography, 


36 


thickness.  Before  receiving  the  litho- 
graphic ink,  the  face  is  carefully  and 
highly  polished,  and  the  stone  made  of 
exactly  the  same  thickness  throughout. 
Some  stone  is  obtained  in  this  country, 
but  it  is  too  coarse  for  fine  work.  Litho- 
graphic ink  is  composed  of  tallow,  wax, 
soap  and  shellac,  about  equal  weights, 
and  quantum  sufficit  of  fine  Paris  black. 
It  may  be  purchased  in  almost  any 
market. 

The  transfer  paper  is  prepared  by 
coating  the  surface  with  a  composition  of 
size  or  starch  and  glue,  with  a  little  gam- 
boge. This  forms  an  excellent  body  for 
the  reception  of  the  ink,  preventing  the 
paper  from  absorbing  it,  and  allows  it  to 
be  readily  transferred  to  the  stone.  The 
drawing  is  made  on  this  paper  with  the 
ordinary  instruments,  when  completed 
it  is  placed  on  the  prepared  stone,  face 
down,  and  is  run  through  the  press ;  the 
paper  is  then  carefully  pulled  off,  leaving 
the  lithographic  ink  on  the  stone.  The 
stone  is  then  slightly  etched  by  pouring 
on  it  a  very  dilute  acid,  giving  the  inked 


37 


lines  a  little  greater  relief.  The  work  is 
then  proven.  Alterations  may  be  made 
by  simply  scratching  off  the  ink  with  a 
penknife  or  common  eraser.  The  sur- 
face is  kept  moistened  with  water  through- 
out the  printing,  and  thousands  of  copies 
may  be  struck  off  of  the  same  stone  with- 
out a  renewal  of  the  drawing  I  saw 
some  very  fine  specimens  of  map  work 
being  done  by  Messrs.  Julius  Bien  &  Co., 
for  the  Coast  Survey  office,  and  also  for 
the  Census  Bureau. 

There  is  but  little  difficulty  in  producing 
excellent  prints  of  pure  line  work  by  any 
of  the  processes  described.  It  is  the 
shading — the  fine  gradations  from  light 
through  half  tints  to  the  strong  darks 
that  call  for  the  skill  of  the  artist.  It  is 
quite  common  for  lithographers  to  print 
from  etched  stones,  especially  in  the 
copying  of  small  detailed  drawings. 
The  surface  of  the  stone  is  smoothed 
and  polished  as  before  described;  it  is 
then  coated  with  a  ground  of  Paris  black. 
The  drawing  is  then  made  with  sharp 
steel  needles  fixed  in  cane  handles,  leav- 


38 


ing  clean  white  lines  on-  the  face  of  the 
stone  ;  these  lines  are  filled  with  the  fatty 
ink ;  the  surface  of  the  stone  is  cleaned 
with  water  and  a  piece  of  coarse  flannel* 
and  is  then  ready  for  the  operator,  or  the 
ground  may  be  removed  and  the  stone 
cleaned,  and  the  lithographic  ink  be  ap- 
plied to  the  surface  of  the  stone  with  a 
roller.  The  lines  scratched  in  will  re- 
ceive no  ink,  and  we  obtain  white  lines  on 
a  black  ground.  Lithographic  chalk  is 
often  used  for  shading  of  large  surfaces, 
and  is  applied  m  the  same  manner  that 
we  apply  pencil  shading.  Fine  shading 
on  small  surfaces,  such  as  the  shadows 
and  gradations  on  a  face,  is  frequently 
stippled  in  with  a  lithographic  pen,  which 
is  similar  in  shape  to  the  ordinary  writing 
pen,  but  is  stronger,  and  is  unsplit. 

In  searching  for  a  process  for  the  pro- 
duction of  maps,  of  which  a  large  num- 
ber of  copies  may  be  desired,  making 
economy  necessary,  I  doubt  if  one  better 
than  lithography  can  be  found,  certainly 
not  in  our  country.  The  most  excellent 
maps  of  the  "Wheeler  survey  were  made 


in  Vienna  by  a  secret  process  belonging 
to  the  Austrian  Government.  Lithography 
proved  of  great  value  to  General  Sher- 
man's army  on  the  march  from  Atlanta  to 
the  sea.  A  wagon  was  fitted  up  with 
a  hand-press,  half  a  dozen  small  litho- 
graphic stones  and  the  necessary  materi- 
als. An  operator  was  found,  who,  in  ad- 
dition to  being  a  good  draughtsman^ 
understood  the  method  of  printing.  The 
reconnoisance  sketches  and  reports  made 
during  the  day  were  turned  over  to  him 
in  the  evening,  and,  by  the  following 
morning,  lithograph  copies  were  in  the 
j)ossession  of  the  officers  entitled  to  them 
Many  of  the  models  now  in  the  Academy 
bearing  the  names  of  Calame,  Harding, 
Julien  are  excellent  examples  of  the  beau- 
ty and  finish  of  lithographic  work  of  some 
twenty  to  thirty  years  ago. 

General  Abbott,  in  some  notes  sub. 
mitted  to  the  chief  of  engineers,  speaks 
of  some  impressions  obtained  by  treating 
a  newspaper  picture  with  acid  and  trans- 
ferring the  printer's  ink  to  the  stone.  He 
says  the  effect  was  fine,  resembling  an 


40 


old  etching.  I  was  told  by  a  prominent 
lithographer  that  the  process  is  known 
in  this  country,  but  is  not  considered  to 
be  of  any  value,  as  a  wood-cut  is  a  poor 
basis  on  which  to  form  a  high  grade 
picture,  much  better  results  can  be  ob- 
tained by  copying  the  wood-cut  directly 
on  to  the  stone. 

Photolithography. — There  are  .several 
photolithographic  processes,  similar  in 
principle,  but  different  in  detail.  Photo- 
graphy is  brought  into  use  as  a  valuable 
aid  to  lithography.  There  is  nothing  to 
prevent  the  direct  formation  of  the  image 
on  the  lithographic  stone  by  exposure 
under  the  negative ;  but  it  would  be 
difficult  to  handle  stones  of  any  con- 
siderable size.  The  result  can  be  ob- 
tained in  the  following  manner :  A  mix- 
ture of  water,  albumen  (white  of  eggs),  or 
of  dry  albumen,  and  bichromate  of  am- 
monia is  passed  over  a  lithographic  stone, 
which  has  been  thoroughly  polished  and 
cleaned.  The  excess  of  the  sensitizing 
mixture  is  carefully  rubbed  off,  and  the 
surface  of  the  stone  dried,  so  as  to  re- 


move  all  traces  of  humidity.  It  is  then 
exposed  under  the  negative.  Wherever 
the  light  has  penetrated  to  the  bichro- 
mated  albumen  it  has  rendered  it  im- 
permeable to  water,  while  the  other  parts 
remain  soluble.  After  sufficient  exposure 
the  stone  is  carried  to  the  dark  room, 
and  the  surface  is  uniformly  covered  with 
lithographic  ink  ;  it  is  then  immersed  in 
a  basin  of  water  and  the  soluble  parts 
are  washed  out,  leaving  the  image  on  the 
stone, which  is  then  treated  with  the  acid 
and  gummed,  and  is  printed  from  as  in 
the  ordinary  lithographic  process. 

The  difficulty  of  handling  the  stones 
has  given  rise  to  the  use  of  a  transitory 
support  for  the  image  and  a  transfer  of 
this  to  the  lithographic  stone.  From 
such  transferred  prints  the  original  draw- 
ing is  reproduced  by  ordinary  surface 
printing. 

The  paper  which  is  to  receive  the  image 
should  be  unsized  and  be  tough  and  not 
easily  torn  or  stretched.  It  is  sensitized 
by  immersion  for  three  or  four  minutes 
in  the  following  solution  : 


42 


Potassum  di-ehromate  44  grammes. 
Gelatine  44  to  60  „ 

Little  Glycerine  water  1  litre, 

and  is  then  hung  up  to  dry.  As  soon  as 
it  is  dry  it  is  exposed  under  the  negative. 
After  exposure  the  surface  of  the  gela- 
tine film  is  carefully  covered  with  a  coat- 
ing of  lithographic  transfer  ink,  either 
with  a  roller,  or  by  putting  ifc  face  down 
on  a  lithographic  stone,  which  has  been 
coated  with  the  ink,  and  subjecting  it  to 
light  pressure.  The  picture  is  then  de- 
veloped by  floating  the  print,  back  down- 
wards, on  a  dish  of  water,  at  a  tempera- 
ture of  about  50°c.  As  soon  as  the  lines 
appear  as  depressions  on  the  film  it  is 
immersed  in  a  warm  water  bath,  to  which 
a  little  alum  should  be  added.  The 
soluble  gelatine  is  carried  away,  together 
with  the  ink  that  covered  it,  and  the 
image  remains  formed  of  ink  lines  in 
relief  on  a  gelatine  back.  This  is  re- 
inked  with  the  roller,  and  is  transferred 
to  the  lithographic  stone,  as  in  ordinary 
lithography.  This  process  lends  itself 
most  readily  to  the  execution  of  line  work. 


43 


The  original  drawing  should  admit  of 
some  reduction  in  size,  as  the  lines  are 
slightly  increased  in  width  by  this  proc- 
ess. Some  very  good  results  have  been 
obtained  by  this  process,  in  the  reproduc- 
tion of  half  tints. 

It  may  be  necessary  to  use  a  sponge 
and  tepid  water  for  arresting  the  de- 
velopment. Various  modifications  of  this 
process  have  been  tried,  but  without  any 
particular  increase  of  excellency  in  work. 

The  word  lithography  has  long  lost  its 
etymological  meaning.  It  is  now  applied 
indifferently  to  any  impression  made 
from  an  inkable  surface  by  reason  of  the 
inverse  affinities  developed  thereon  for 
water  and  greasy  ink. 

Chromo-Lithography.— Chromo-lithog- 
raphy  is  simply  lithography  in  colors, 
and  differs  in  no  wise  from  ordinary 
lithography.  It  is  a  much  more  labo- 
rious process,  as  a  separate  stone  must 
be  made  for  each  color,  and  it  is  con- 
sequently more  expensive  and  slower 
than  lithography  in  black.    No  better 


specimens  of  chromo-lithograpkic  work 
can  be  found  than  the  many  beautiful 
cards  printed  on  paper  and  also  on  satin 
by  Messrs.  Prang  &  Co.  It  is  the  great 
commercial  process  of  the  day,  .and  enor- 
mous quantities  of  this  kind  of  work  are 
required  to  meet  the  demands  of  industry 
and  commerce.  The  difference  between 
the  show-bill  and  the  satin  card  is  not 
due  to  the  process,  but,  as  in  everything 
else,  to  the  quality  of  the  materials  used, 
and  the  skill  and  artistic  taste  and 
knowledge  of  the  makers. 

Great  care  is  necessary  in  making  the 
drawings  on  the  different  stones,  so  that 
the  various  colors  shall  fit  accurately  into 
their  places  in  the  drawing.  A  "  key- 
stone "  is  first  executed  and  proved ; 
marks  or  small  needle-holes  are  made  for 
"  registering "  particular  points  of  the 
drawing.  This  u  keystone  "  is  only  used 
for  making  as  many  impressions  on  the 
other  stones  as  there  are  colors  to  be  em- 
ployed. I  saw  preparations  for  the  print- 
ing of  a  card  for  which  seventeen  stones 
were  to  be  used,  and  copies  of  this  card 


45 


could  probably  be  bought  for  from  15  to 
25  cents. 

I  have  read  a  description  of  Mr.  Eck- 
stein's new  method  for  reproducing  maps 
and  drawings,  for  which  he  claims  the 
following  advantages : 

1st.  A  color  is  printed  in  all  its  shades 
by  means  of  one  stone. 

2d.  All  colors  are  printed  by  means  of 
but  three  stones. 

It  answers  very  well  for  map  work,  as 
all  of  the  necessary  colors  can  be  readily 
obtained  by  the  simple  superposing  of 
the  primaries — blue,  yellow  and  red  ;  but 
for  the  reproduction  of  art  works,  in 
which  great  varieties  of  color  and  tone  are 
necessary,  I  am  told  it  does  not  answer 
so  well  as  the  ordinary  chromo-litho- 
grapbic  process. 

His  process  is  substantially  as  follows : 

A  photographic  negative  of  the  object 
is  taken,  from  which  a  positive  image  is 
formed  on  glass.  This  image  is  con- 
secutively transferred  to  the  three  pre- 
pared stones.  Each  stone  is  then  polished 
and  lightly  coated  with  a  mixture  of  as- 


46 


phalt,  white  wax,  stearine  and  a  solution 
of  soda  ;  it  is  then  exposed  to  the  light, 
which  makes  the  coating  insoluble  to  a 
limited  extent.  It  is  then  dried  and 
placed  under  a  line  drawing  machine, 
which  covers  the  whole  surface  of  the 
stone  with  fine  parallel  lines,  by  means 
of  a  blunt  diamond,  which  takes  away 
the  coating  without  cutting  the  stone. 
The  stone  is  then  etched  at  the  pleasure 
of  the  operator,  as  in  ordinary  etching, 
and  on  this  depends  the  success  of  the 
operation ;  so  that  the  skill  of  a  practised 
etcher  is  necessary  after  the  etching  is 
finished.  The  surface  of  the  stone  is 
washed  writh  turpentine,  and  the  rem- 
nants of  asphalt  and  ink  removed.  The 
color  is  then  rubbed  on,  and  the  stone  is 
ready  for  impression. 

His  process  for  printing  all  gradations 
of  a  single  color  works  admirably  in 
topographical  maps ;  but  for  the  repro- 
duction of  art  works,  his  process  is  more 
artistic  than  mechanical,  without  corre- 
sponding results. 

Oleography. — This  is  a  name  given  to 


47 


a  merely  vulgar  process,  which  is  simply 
an  attempt  to  adapt  chromo-lithography 
to  the  purposes  of  imitating  oil  paintings. 
The  print  is  mounted  on  canvas,  sized 
and  varnished,  and  is  sold  under  the 
ordinary  name  of  "  Chromo." 

Zincogkaphy. — This  process  is  simply 
lithography  applied  to  zinc  plates  instead 
of  to  the  stone.  Zinc  plates  are  cheaper, 
and  more  readily  transported;  but  as 
the  ink  does  not  penetrate  the  zinc  as  it 
does  the  stone,  the  adhesion  is  not  so 
strong,  and  accidents  are  liable  to  occur 
in  the  printing  which  would  require  the 
preparation  of  a  new  plate. 

Hoeschotype. — This  is  a  new  process 
of  color  printing  in  fac-simile,  named 
after  the  German  inventor.  The  follow- 
ing advantages  are  claimed  for  it  over 
chromo-lithographic  processes :  More 
delicate  gradations  of  tint  and  greater 
simplicity  of  processes,  which  requires 
only  five  printings,  and  its  therefore  im- 
mensely diminished  cost ;  also  the  almost 
unlimited  number  of  copies  to  be  ob- 
tained from  the  plates.    First  comes  the 


48 


copy  in  photography  and  the  transfer  to 
the  metallic  plates,  which  are  prepared 
with  gelatine.  Five  such  copies  are 
treated  successfully  with  the  required 
proportions  of  yellow,  red,  blue,  neutral 
and  brown  pigments,  and  the  printings 
are  taken  off  in  the  same  manner.  Under 
this  process,  by  the  adjustment  of  the 
relative  proportions  of  the  five  combined 
colors,  it  professes  to  cover  1,620  dif- 
ferent tints.  The  specimen  prints  show 
surprising  delicacy  and  variety  of  tone. — 
Portfolio. 

Cerography — A  cerograph,  as  the  name 
implies,  is  a  drawing  in  wax.  The  earliest 
development  of  cerography  consisted  in 
making  a  drawing  in  a  wax  coating  on  a 
metal  plate.  The  lines  were  drawn  with 
an  ivory  point,  and  were  cut  through  the 
wax  to  the  surface  of  the  metal,  a  mould 
of  the  wax  was  then  taken  and  stereo- 
typed. Electrotypy  has  superseded  the 
unsatisfactory  stereotypic  process ;  but 
otherwise  the  process  of  to-day  is  the 
same.  Messrs.  Struther,  Servoss  &  Co., 
of  New  York,  do  a  great  deal  of  this  kind 


49 


of  work,  and  furnish  some  very  hand- 
some prints.  It  is  exceedingly  well  adapt- 
ed to  the  reproduction  of  small  maps, 
mechanical  and  engineering  drawings, 
small  landscapes  and  other  illustrations 
without  difficult  gradations  in  light  and 
shade. 

A  copper  plate,  about  of  an  inch  in. 
thickness,  is  slightly  oxydized  on  one 
face,  and  this  face  is  covered  with  a 
coating  of  white  wax,  the  composition  of 
which  is  a  secret.  This  coating  is  made 
of  about  the  thickness  of  a  sheet  of  blot- 
ting-paper, and  is  kept  perfectly  clean 
and  smooth.  The  wax  must  be  of  such 
a  nature  that  it  will  adhere  firmly  to  the 
plate  in  the  parts  not  cut  away,  and  yet 
must  be  easily  removed  by  the  V  shaped 
drawing  instrument.  The  drawing  is 
made  on  the  wax,  either  by  hand,  or  it  is 
photographed  directly  from  the  original 
to  the  wax  by  a  process  not  made  public. 
The  drawing  completed,  the  lines  are  cut 
out  of  the  wax,  just  to  the  surface  of  the 
copper.  The  lettering  of  maps  is  put  in 
by  simply  pressing  the  type  in  the  wax, 


50 


so  as  to  leave  a  clean  sharp  impression  of 
it  in  the  proper  place.  The  drawing  is 
then  "  built  up  "  with  beeswax,  so  as  to 
give  the  electrotype d  lines  sufficient 
relief.  After  the  "  building  up  "  is  com- 
pleted, the  plate  is  electrotyped  in  the 
usual  way. 

They  also  do  some  very  good  work  in 
colors,  and  use  only  the  three  primaries 
red,  yellow  and  blue.  They  get  a  suffi- 
cient number  of  tints  for  map-work  by 
superposing  these  colors,  as  in  chromo- 
lifchography.  A  separate  relief  block 
must  be  made  for  each  of  the  primary 
colors.  In  preparing  the  plates  for 
colored  work,  the  waxed  face  is  put  under 
a  line  drawing  machine,  and  is  ruled  in 
to  the  surface  of  copper.  The  electro- 
types taken  from  these  surfaces  give 
beautiful  prints  in  the  ordinary  rapid 
steam  press.  The  work  done  by  this 
process  is  certainly  most  excellent.  It  is 
reasonably  cheap  and  rapid,  and  is  only 
executed  m  two  places  in  our  country. 

The  process  of  M.  Dulos  is  as  follows: 


51 


A  plate  of  copper  is  covered  with  the  fol- 
lowing mixture : 

Ordinary  Benzine^ 


Zinc,  white  ) 

This  coating  can  be  easily  cut  with 
steel  or  ivory  points.  The  drawing 
finished,  the  plate  is  plunged  into  an  iron 
bath,  which  deposits  the  iron  only  on  the 
uncovered  copper.  If  we  desire  to  ob- 
tain an  engraved  plate,  the  varnish  is 
removed  and  the  plate  is  silvered.  The 
silver  is  deposited  on  the  copper,  to  the 
exclusion  of  the  iron,  by  pouring  a  dilute 
solution  of  sulphuric  acid  on  the  plate. 
The  iron  is  eaten  out,  and,  by  treating 
the  plate  with  the  ammoniacal  sulphate  of 
mercury,  the  relief  of  the  silvered  parts 
is  slightly  increased,  and  we  have  the 
lines  in  intaglio. 

A  relief  plate  may  be  obtained  of  the 
same  drawing  by  depositing  silver  in 
place  of  the  iron. 

The  process  of  M.  Comte,  for  produc- 
ing a  typographic  plate,  is  somewhat 


Caoutchouc 


52 

similar  to  that  of  M.  Dulos.  He  used 
the  following  solution : 

Gum  Arabic  ^  Mixed  to  a  con- 
Zinc,  white  V  venient  con- 
Avignon,  yellow)  sistency. 

This  solution  is  placed  on  a  zinc  plate, 
which  has  been  carefully  prepared.  The 
lines  are  removed  with  a  quill  or  an  ivory 
point,  leaving  the  naked  metal.  Lith- 
ographic ink  is  daubed  into  the  lines, 
and  the  plate  is  cleaned  with  benzine,  so 
as  to  remove  all  of  the  varnish,  after 
which  the  plate  is  dampened  and  inked 
anew.  The  ink  is  received  only  by  the 
lines  which  have  previously  been  in  con- 
contact  with  the  greasy  ink.  A  resinous 
powder  is  now  carefully  sprinkled  on  the 
greasy  ink,  and  the  plate  is  subjected  to 
the  action  of  dilute  acid,  until  the 
desired  relief  is  obtained.  The  greasy 
resinous  varnish  protects  the  lines  of  the 
drawing  from  the  action  of  the  acid. 
These  processes  are  not,  as  will  be  readily 
seen,  purely  cerographic,  but  are  allied 
to  it. 


53 


For  industrial  uses,  electrotypy  answers 
much  better  than  the  purely  chemical 
processes,  based  on  the  use  of  the  salts  of 
mercury.  By  making  a  good  drawing 
in  the  wax,  applying  a  coating  of  black 
lead  and  electrotyping,  an  excellent  plate 
can  be  obtained,  having  the  additional 
essentials  of  cheapness  and  rapidity  of 
execution.  The  wax  must  have  similar 
properties  to  that  used  in  etching.  The 
following  formulas  give  satisfactory  re- 
sults : 

A.  Pure  wax  (white) 
Burgundy  Pitch 
Kesin 
Asphalt 
Turpentine 

B.  White  wax 
Asphalt 
Black  Pitch 
Burgundy  Pitch 

Photography. — It  will  not  be  possible, 
within  the  necessary  limits  of  this  article, 
to  give  more  than  a  general  outline  of 


75  grammes. 

90 

15 

60 

a  few  drops. 


60  grammes. 

60 

30 

15 


54 


the  principal  operations  in  photography. 
It  is  a  science  of  optics  and  chemistry 
combined.  Its  rapid  progress,  and  the 
wonderful  developments  in  its  various 
applications  in  the  past  twenty  years 
have  spread  it  over  almost  every  branch 
of  human  effort  and  knowledge.  In 
astronomy,  geography,  lithography  in 
artistic  reproductions  of  valuable  works, 
and  in  the  departments  of  justice,  its 
value  cannot  be  overestimated.  Its  utility 
in  time  of  war,  and  its  value  to  the  mili- 
tary man,  was  clearly  shown  in  the  war 
of  1870-71,  and  its  range  has  manifestly 
widened  since  that  time.  In  some  foreign 
schools  of  technology  it  is  carefully 
taught.  It  will  reproduce  in  minutes,  work 
which  required  weeks  and  months  of 
hard  and  careful  work,  and  with  far 
greater  accuracy  than  could  be  obtained 
by  any  other  method.  It  takes  long 
practice  and  some  natural  ability  to  make 
a  good  draughtsman.  A  few  months  of 
careful  instruction  in  photography  is 
sufficient.  Good  apparatus  can  now  be 
bought  at  very  low  rates.   It  gives  ample 


55 


returns  in  instruction  and  amusement 
for  all  of  the  time  spent  in  studying  its 
various  applications. 

Before  describing  the  various  detailed 
operations,  it  will  be  necessary  to  briefly 
give  the  principles  which  make  photog- 
raphy possible 

Various  substances,  such  as  the  salts 
of  silver,  some  of  the  salts  of  iron,  urani- 
um and  chromium,  potassium  dichromate, 
and  a  certain  kind  of  asphaltum  or  bitu- 
men found  in  Judea,  when  exposed  to 
action  of  the  actinic  or  chemical  rays  of 
light  undergo  peculiar  chemical  changes, 
and  if  in  the  presence  of  some  organic 
substance,  such  as  collodion,  gelatine,  etc., 
they  form  new  compounds  with  peculiar 
properties  as  to  solubility.  The  parts 
acted  upon  by  the  light,  become  nearly 
insoluble  in  water,  turpentine,  etc.,  while 
the  parts  screened  from  the  light  remain 
soluble  and  are  easily  washed  out.  This 
action  is  so  perfect  that  it  extends  admi- 
rably through  the  half  tones  and  delicate 
gradations,  enabling  us  to  get  a  complete 
detailed  picture.    The  extent  of  the 


56 


action  depends  upon  the  intensity  of  the 
light  and  the  time  of  exposure  of  the 
sensitive  plate.  The  actinic  rays  are 
found  in  the  green,  blue,  blue  violet  and 
violet  rays  of  the  spectrum,  and  are  very 
weak  in  the  yellow  and  red  rays  ;  so  that 
the  colors  which  appear  brightest  on  the 
retina  have  the  least  effect  on  the  negative 
plate.  This  explains  why  yellow  and  red 
objects  print  dark  on  the  picture,  and 
blue  and  violet  print  white.  The  process 
of  taking  a  picture  by  photography  may 
be  divided  into  the  following  distinct 
operations : 

(1.)  The  Formation  of  the  Sensitive 
Plate. — Glass  is  found  to  be  the  most  sat- 
isfactory material  to  form  the  negative  on; 
where  but  a  single  copy  is  desired  it  may 
be  taken  on  paper,  wood,  or  other  sub- 
stance. The  glass  should  be  clear  and 
must  be  thoroughly  cleaned  just  before 
the  sensitive  solution  is  placed  on  it,  as 
any  specks  of  dust  or  grease  spots  on  its 
face  will  injure  the  negative.  It  should 
be  immersed  in  a  bath  of  nitric  acid  and 
then  thoroughly  dried  and  rubbed  with 


57 


a  dry  cloth.  It  is  then  ready  for  the 
collodion,  which  is  almost  universally 
used  for  a  body,  as  it  is  particularly  suit- 
able for  holding  the  precipitable  salts  of 
silver,  and  is,  for  ordinary  purposes, 
totally  unacted  upon  by  the  sensitising 
solution.  The  plate  is  held  by  one  cor- 
ner, and  a  circular  mass  of  the  thick  fluid, 
to  which  a  metallic  iodide  and  a  bromide, 
as  of  potassium,  have  been  added,  is 
poured  upon  the  center  and  allowed  to 
flow  to  each  of  the  four  corners  by  a 
gentle  inclination  of  the  plate,  about  half 
of  the  fluid  remains  and  adheres  to  the 
plate,  the  remainder  is  poured  off  at  a  cor- 
ner. As  soon  as  the  collodion  stiffens, 
the  plate  is  immersed  in  the  nitrate  of 
silver  bath.  This  is  accompanied  by  a 
chemical  change.  The  iodine  and  bromine 
salts  change  properties  with  the  nitrate 
of  silver,  and  give  birth  to  the  iodide  and 
the  bromide  of  silver  and  nitric  acid  salts. 
All  of  these  details  having  been  carefully 
conducted  in  a  dark  room,  or  in  a  room 
to  which  light  is  admitted  through  a 
yellow  or  1  aby  colored  glass,  the  plate 


58 


is  placed  in  the  cassette  or  dark  slide, 
and  is  ready  for  the  camera,  and  the 
second  stage  of  the  operation,  or 

(2).  The  Development  of  the  Images. — 
The  object  is  carefully  placed  in  the 
focus ;  the  cassette  is  put  in  the  camera: 
the  slide  is  drawn  out,  and  the  light  is 
allowed  to  fall  on  the  sensitive  plate. 
This  is  a  very  important  operation.  If 
the  time  of  exposure  is  too  short,  the 
picture  will  be  weak,  if  it  be  exposed 
for  too  long  a  time  the  bright  lights  will 
appear  as  great  white  blotches.  The  time 
must  be  regulated  by  the  nature  and  in- 
tensity of  the  light,  and  is  different  for 
differently  sensitized  plates.  It  can  be 
learned  only  by  experience.  The  chemi- 
cal strength  of  the  blue  sky  light  varies 
greatly  with  the  latitude  of  the  place, 
the  season  of  the  year,  and  the  time  of 
day — southern  latitudes.  The  summer 
season  and  mid-day  give  the  most  favor- 
able opportunities.  Electric  calcium  and 
magnesium  lights  are  actinic;  moon- 
light, lamp  and  gas  light,  but  very 
slightly  so.    After  sufficient  exposure, 


59 


the  slide  is  replaced  and  the  plate  re- 
moved to  the  dark  room.  The  image  is 
as  yet  invisible,  and  must  be  brought  out 
and  developed  by  some  chemical  agent. 
The  light  has  peculiarly  affected  the 
iodide  of  silver,  the  principal  constituent 
of  the  plate,  changing  it  from  the  iodide 
Ag2I2  into  the  subiodide  Ag2I,  leaving  but 
one  atom  of  silver  saturated  and  the 
other  free  to  combine  with  any  substance 
for  which  it  may  have  an  affinity.  A  so- 
lution of  green  vitriol  (Ferrous  sulphate) 
is  gently  poured  on  the  plate.  The  silver 
is  precipitated  on  the  plate,  and  the 
picture  slowly  makes  its  appearance; 
first  the  lightest  parts,  such  as  the  shirt 
and  the  face,  then  the  darkest.  The 
picture  may  not  be  strong  enough  yet, 
and  must  now  be  put  through  the  op- 
erations of 

(3).  Intensifying  and  Fixing. — After 
the  development  the  plate  is  washed  with 
clean  water,  and  the  picture  is  intensified 
by  repeating  the  process  of  development. 
A  mixture  of  green  vitriol  and  a  solution 
of  silver  is  poured  upon  the  plate  and 


60 


more  silver  is  thus  precipitated.  After 
the  image  has  been  sufficiently  intensi- 
fied, in  the  judgment  of  the  operator,  it 
is  fixed  by  pouring  on  the  plate  a  solution ' 
of  the  hypo-sulphite  of  sodium,  or  the 
cyanide  of  potassium.  This  dissolves 
out  the  surplus  salts  of  silver,  leaving  the 
image  intact  in  metallic  silver.  The 
plate  is  now  washed  and  dried  and 
covered  with  a  varnish  for  protection,  and 
is  ready  for  the 

(4).  Printing. — The  negative  shows 
everything  reversed — the  white  face  is 
black  and  the  black  coat  is  white,  hence 
a  positive  must  be  obtained  from  this. 
It  is  also  evident  that  the  relations  of 
light  and  shade  are  not  correct ;  all 
defects  in  the  original  are  faithfully  re- 
produced in  the  negative  ;  and,  indeed, 
so  sensitive  is  the  plate,  that  many  marks 
on  the  object,  not  visible  to  the  eye,  show 
plainly  as  spots  on  the  negative.  Vogel 
relates  an  incident  in  the  taking  of  a 
portrait  of  a  lady,  on  which  many  dark 
spots  were  found  on  the  negative  of  the 
face.   As  the  lady  had  a  fairly  good  com- 


61 


plexion,  these  spots  excited  the  curiosity 
of  the  photographer,  and  he  learned  that 
three  days  afterwards  she  was  taken  ill 
with  the  small  pox.  The  negative  had 
forestalled  the  eye  in  its  detection  of  the 
disease. 

These  defects  were  formerly  marked 
out  of  the  pictures  as  they  were  printed, 
but  now  they  are  changed  on  the  negative, 
which  is  carefully  retouched  with  a 
camel's  hair  brush  and  India  ink  or  ver- 
milion. A  piece  of  paper,  coated  with 
the  white  of  egg,  and  moistened  with  a 
solution  of  kitchen  salt,  is  laid  in  a  dish 
containing  a  solution  of  nitrate  of  silver. 
Chloride  of  silver  is  formed  on  the  surface 
of  the  paper  through  the  action  of  the 
salt  (chloride  of  sodium).  The  white  of 
egg  takes  the  place  of  the  collodion  used 
on  the  negative.  The  paper  is  now  dried 
in  the  dark  and  becomes  fully  sensitized. 
It  is  then  placed  in  the  printing  frame, 
under  the  negative,  and  is  exposed  to  the 
light.  A  faithful  positive  is  formed  on 
the  paper.  It  is  then  removed  to  the  dark 
room,  and  the  superfluous  salts  washed 


62 


out,  as  described,  for  the  negative.  It  is 
then  immersed  in  the  hypo-sulphate  of 
sodium  solution,  from  which  it  un- 
fortunately suffers  a  disagreeable  change 
of  color,  and  must  be  toned  down ; 
this  is  effected  by  immersing  it  in  a  di- 
lute solution  of  chloride  of  gold.  It  is 
then  fixed  with  the  hypo- sulphite  and 
thoroughly  washed,  after  which  it  is  dried 
out  into  regular  shape,  mounted  on  card- 
board, touched  up,  and  rendered  glossy 
by  two  smooth  steel  rollers.  Such  is 
substantially  the  wet-plate  process  of 
photography. 

The  dry-plate  process  is  much  more 
convenient  for  amateurs,  as  the  plates 
can  be  purchased  ready  for  use,  and  will 
remain  good  for  long  periods  if  kept  in  a 
dark  and  dry  place. 

These  plates  are  prepared  in  the  same 
manner  as  the  wet  plates,  except  that  the 
addition  of  some  organic  substance,  such 
as  tannin,  morphine,  caffeine,  having 
chemical  relation  with  iodine,  is  necessary, 
as  it  allows  the  coating  to  become  dry 
without  injury.    After  being  dried,  the 


63 


plates  are  given  a  light  coating  of  var- 
nish for  protection.  Pyrogallic  acid  and 
a  solution  of  silver  is  used  in  the  develop- 
ment and  intensifying.  Potassium  oxa- 
late and  ferrous  sulphate  may  be  used  in 
the  development.  The  negative  is  fixed 
with  the  hyposulphite  of  sodium. 

Instantaneous  Photogeaphy. — This  is 
an  important  feature  in  the  study  and 
practice  of  the  science  of  photography. 
It  is  particularly  valuable  to  the  military 
profession.  It  enables  us  to  obtain  beau- 
tiful and  accurate  representations  of  the 
effects  of  torpedo  explosions,  the  explo- 
sion of  mines,  the  firing  of  heavy  guns 
at  experimental  targets,  movements  of 
troops  on  the  field  at  any  particular 
moment,  etc.  One  of  the  various  emul- 
sion processes  is  generally  used,  pref- 
erably the  gelatino-bromide  process;  it 
gives  very  sensitive  plates.  The  medium 
used  for  holding  the  sensitive  salts  in 
solution  is  gelatine,  which  gives  valuable 
qualities  to  the  image.  They  are  pre- 
pared with  an  excess  of  the  sensitive  salt, 
preferably  the  bromide  of  silver. 


64 


The  gelatine  is  soaked  in  water  and 
heated,  while  the  solution  is  hot,  potass- 
bromide  is  added  and  then  the  silver 
nitrate,  with  constant  stirring, ;  the 
emulsion  is  then  poured  into  a  dish  and 
allowed  to  set ;  after  setting  it  is  cut  into 
strips  and  washed  for  several  hours,  with 
constant  changes  of  water.  It  is  then 
dried,  and  is  warmed  and  poured  on  the 
plate.  The  operations  of  developing,  in- 
tensifying and  printing  are  the  same  as 
described  for  the  ordinary  negative ; 
greater  time  is  necessary  in  developing 
and  intensifying.  Pyrogallic  acid  pot- 
bromide,  a  little  ammonia  and  distilled 
water  may  be  used  in  developing  and 
intensifying,  and  the  hypo- sulphite  for 
fixing.  *  *  *  * 

The  science  of  photographing  colors 
is  not  yet  fully  developed ;  enough  has 
been  accomplished  to  show  the  possibility 
of  it ;  and  we  may  expect  the  discovery 
of  the  secret  at  no  very  distant  day.  In 
fact  a  German  photographer  has  suc- 
ceeded in  taking  some  good  color  work, 
but  it  fades  out  very  quickly.  "With  the  de- 


65 


velopment  of  this  branch  of  photography- 
its  range  will  be  vastly  increased.  Pic- 
tures of  nature,  copies  of  the  many 
beautiful  works  of  the  old  and  of  the 
modern  masters,  true  in  all  of  the  details 
of  color  and  light  and  shade  will,  we  trust, 
soon  supersede  the  many  poor  and  false 
pigment  prints  now  forced  on  the  public. 

In  connection  with  the  discussion  of 
photography  in  colors,  it  may  be  interest- 
ing to  learn  something  of  the  work  already 
accomplished. 

We  know  that  the  solar  spectrum  is 
composed  of  seven  distinct  colors — violet? 
indigo,  blue,  green,  yellow,  orange  and 
red.  These  colors  are  indecomposable, 
however.  If  we  project  red  on  blue  we 
get  the  violet,  yellow  and  blue  give  green, 
and  yellow  and  red  give  orange  rays.  We 
have  then 

Violet    ==  red  +  blue. 
Indigo  =  violet  +  blue. 
Green    ==  blue  +  yellow. 
Orange  =  yellow  -f-  red. 

If  we  combine  the  common  factors,  we 


66 


get  violet  4-  indigo  +  green  -f  orange = red 
+  yellow  +  blue.  That  is  to  say,  with 
combinations  of  red,  yellow  and  blue  we 
can  reproduce  all  of  the  colors  of  the 
spectrum.  If,  then,  we  look  at  an  object 
through  a  green  glass,  the  rays  which 
pass  through  the  glass  and  reach  our 
eyes  are  found  in  the  blue  and  yellow 
regions  of  £he  spectrum,  the  red  rays 
being  stopped  out  by  the  green  glass. 
With  an  orange  glass  the  blue  rays  are 
arrested,  and  with  a  violet  glass  the 
yellow  rays  are  stopped.  "We  come  now 
to  the  following  synopsis  : 


Green  glass  -s  j  i      f  red  isolated, 


If,  then,  we  make  three  negatives,  in- 
terposing between  the  sensitive  plate  and 
the  object ;  first  a  green  glass,  then  an 
orange,  then  a  violet  one,  we  will  get 
plates  upon  which  for  the  first,  the  red 


Violet 


Orange 


67 


rays  will  have  had  the  least  effect,  for  the 
second  the  blue,  and  for  the  third  the 
yellow  rays.  The  process  then  as  used 
by  M.  Gros  and  M.  Ducos,  du  Hauron, 
consists  in  the  production  of  three  neg- 
ative plates,  as  described  above,  preserv- 
ing the  same  dimensions  in  each.  The 
negative  obtained  with  the  green  glass 
serves  for  the  printing  of  the  red  mono- 
chrome, the  second  for  the  blue,  and  the 
third  for  the  yellow.  Then  following  the 
idea  of  the  inventors,  the  superposing  of 
these  three  monochromes  should  result  in 
a  reproduction  of  the  colors  of  the  natu- 
ral objects.  But  when  we  think  of  the  com- 
plications and  difficulties  attending  the 
production  of  these  three  separate  neg- 
atives with  the  varying  times  of  exposure, 
made  necessary  by  the  different  actinic 
properties  of  the  glass  plates,  and  added 
to  these  the  complications  of  light  and 
shade,  we  cannot  make  any  serious  com- 
parison between  the  results  and  the  orig- 
inals. As  I  stated  in  the  article  on  pho- 
tography, the  red  rays  of  the  spectrum 
are  practically  non-actinic,  as  the  orange 


68 


and  the  violet  plates  contain  red,  the  pro- 
duction of  the  negatives  from  those  col- 
ors is  attended  with  increased  difficulties. 

M.  Guntrel  conceived  the  idea  of  add- 
ing to  the  three  plates  already  described, 
a  fourth  plate  in  black  from  which  the 
shadows  were  to  be  obtained.  This  proc- 
ess is  interesting  as  showing  what  can 
be  done  in  the  development  of  artistic 
fancy  and  genius,  but  is,  I  should  say, 
more  properly  a  method  of  polychrome 
printing,  than  of  photographing  colors. 
There  exists  in  nature  a  multitude  of 
colors,  grays,  browns,  neutral  tints,  and 
all  gradations  of  violet,  green,  orange, 
&c.  We  can  scarcely  expect  to  repro- 
duce these  accurately  in  pigment  by  the 
superposition  of  the  three  primary  colors, 
red,  yellow  and  blue. 

The  gelatino-bromide  of  silver  process 
is  destined  to  take  the  lead  in  photog- 
raphy, because  of  its  extreme  simplicity, 
its  great  rapidity,  and  the  facilities  it  of- 
fers for  dry  plates.  The  amateur  can 
procure  the  plates  already  prepared,  and 
by  studying  for  a  few  days,  the  manipu- 


69  (lliSTIT 

lations  in  the  development  of  tb$  image 
can  obtain  results  which  were,  until  very 
recently,  in  the  exclusive  domain  of  tlie~ 
specialist.  The  image  may  be  developed 
either  by  using  the  Pyrogallic  acid  bath 
or  a  solution  of  iron.  The  latter  seems 
to  be  preferred  by  prominent  photograph- 
ers. 

Dr.  Munckhoven  used  the  following 
bath : 

In  one-half  liter  of  boiling  water,  dis- 
solve 100  grammes  of  the  neutral  oxalate 
of  potassium,  and  50  grammes  of  ferrous 
lactate  in  powder,  stirring  the  mixture. 
Filter  as  soon  as  cold,  and  add  a  small 
quantity  of  the  following  solution : 

Water   1,000  cent,  cubes. 

Br.  of  ammonia.     100  grammes. 

The  Bromide  solution  slightly  retards 
the  development  of  the  image,  but  de- 
creases the  liability  of  fogged  plates. 

Dr.  Eder,  of  Vienna,  prescribes  the 
following  formula : 

A.  In  a  liter  of  dist.  water  dissolve  300 
grammes  of  pure  sulphate  of  iron,  add  3 
drops  of  sulphuric  acid,  then  filter.  The 


70 


solution  should  have  a  pale  emerald 
green  color. 

B.  In  one  liter  of  dist.  water  dissolve 
300  grammes  of  the  neutral  oxalate  of 
potassium,  then  filter. 

C.  Dissolve  10  grammes  of  bromide  of 
ammonia  in  100  grammes  of  dist.  water. 

To  prepare  the  bath  for  use,  take  3 
parts  of  B,  to  which  add  1  part  of  A,  a 
little  at  a  time  with  constant  stirring. 
This  bath  will  remain  good  for  about  two 
days.  The  quantity  of  C  to  be  added 
depends  upon  the  emulsion  employed, 
and  the  effects  desired  without  the 
chromide.  The  negatives  are  very  soft 
but  are  easily  fogged. 

To  400  cubic-cent,  of  the  developer,  2, 
4,  6'  or  8  cubic- cent,  of  the  bromide  may 
be  added. 

Use  the  hypo-sulphate  for  fixing. 
The  following  "General  Purpose  De- 
veloper n  is  given  by  Lt.  Griffin  : 

Ferrous  sulphate  100  parts 

White  rock  candy         25  " 

Glacial  acetic  acid ....   32  66 

Alcohol   32  « 

Water  1000  " 


71 


This  may  be  strengthened  or  weakened 
by  the  addition  or  subtraction  of  the  sul- 
phate. 

For  intensifying  (Capt.  Abney). 

No  1.  Pyrogallic  acid.  4  grammes. 

Citric  acid  4  to  8  * 

Water   1  liter. 

No.  2.  Ferrous  sulph.  10  grammes. 

Citric  acid  20  " 

Water   1  liter. 

To  each  of  the  above  a  few  drops  of 
the  following  solution  must  be  added  im- 
mediately before  application  to  the  film. 

Silver  nitrate.  20  grammes. 
Water   500  cubic-cent. 

For  fixing  (Munckhoven), 

(1)  Cyanide  of  potassium.  20  grammes. 

Dist.  water   1  liter. 

(2">  Hypo-sulphate  of  so- 
dium.  1 00  grams. 

Dist.  water   1  liter. 

For  silver  nitrate  bath, 


72 


(Wet  process.)  Dist.  water.  1  liter. 


The  cyanide  is  poisonous  and  should 
be  used  very  carefully. 


A  few  drops  of  the  bromide  of  potas- 
sium added  to  the  iron  solution  will  re- 
tard a  too  rapid  development  of  the 
image. 

The  following  defects  in  negatives 
must  be  carefully  guarded  against  and 
steps  taken  to  remedy  them. 

"Fog,"  on  the  negative,  this  may  be 
due,  1st.  To  a  dirty  plate.  2d.  To  im- 
proper exposure  to  the  actinic  rays  either 
in  the  dark  room,  or  in  the  camera.  With 
the  dry  plates ;  storage  in  a  damp  place 
will  injure  the  plates  and  give  clouded 
results.  3rd.  To  want  of  acid  in  the  de- 
veloper. 4th.  To  the  presence  of  vapors 
in  the  developing  room. 

A  weak  image  may  be  due  to  unsuit- 


Nitrate  of  silver. . . . 
Iodide  of  potassium 
Nitric  acid  


80  grammes. 


2  drops 


1    liter    =1.05  quarts. 
1  gramme =15.432  grains. 


73 


able  collodion,  dull  or  cloudy  weather, 
organic  matter  in  the  bath,  or  an  over- 
strong  developer. 

Pin  holes  may  be  caused  by  the  presence 
of  dust  in  the  plate,  or  the  bath  being 
over-iodized.  Black  specks  are  usually 
due  to  dirt  on  the  camera,  or  on  the 
lens,  or  on  the  collodion. 

A  want  of  sharpness  is  often  caused  by 
improper  focusing,  or  by  an  accidental 
shaking  of  the  camera  during  the  expos- 
ure, or  by  slight  unsteadiness  of  the  ob- 
ject. For  most  of  these  defects  the  rem- 
edies are  apparent,  and  practice  will 
soon  enable  the  amateur  to  judge  of  the 
various  causes  of  the  defects  in  his  nega- 
tive. Order  and  cleanliness  and  purity 
of  chemicals  are  necessary  aids  to  good 
work. 

APPLICATIONS  OF  PHOTOGRAPHY. 

The  processes  of  reproduction  based 
on  photography  are  numerous  and  some 
of  them  very  detailed  in  operation.  So 
much  depends  upon  the  skill  of  the  oper- 
ator that  it  is  scarcely  possible  for  an 


74 


amateur  to  obtain  more  than  fair  results. 
It  is  difficult  to  tell  how  much  of  the 
beautiful  work  produced  is  due  to  skill 
in  handling,  and  how  much  to  the  prop- 
erties inherent  to  the  process.  Most  of 
these  processes  are  patented,  and  some 
of  the  most  important  details  are  care- 
fully guarded  secrets.  Enough  is  known, 
however,  to  enable  us  to  describe  the 
methods  of  applying  them  to  the  repro- 
duction of  line  work. 

The  photogravure,  carbon  prints,  and 
heliotypes  seem  to  occupy  prominent 
places  in  public  estimation.  The  first,  as 
produced  by  the  Paris  firm  of  Messrs. 
Goupil  &  Co.,  have  no  superiors  in  the 
line  of  artistic  reproductions.  In  the  re- 
production of  paintings  by  these  proc- 
cesses  much  is  gained  by  photographing 
the  picture,  if  possible,  in  the  same  light 
as  that  in  which  it  was  originally  pro- 
duced. This  enables  the  operator  to  get 
a  correct  negative  so  far  as  the  light  and 
shade  of  the  drawing  or  painting  is  con- 
cerned. 

It  is  quite  difficult  to  make  an  exact 


75 


classification  of  the  various  processes  em- 
ployed. A  very  general  classification 
might  be  made  on  the  following  scheme : 

1.  Collotype  printing,  or  those  proc- 
esses on  which  the  print  is  taken  directly 
from  the  gelatine  film.  To  this  class  be- 
long the  autotype,  albertype,  autoglyph, 
or  indo-tint,  and  the  phototype. 

2.  Those  on  which  the  film  is  transfer- 
red to  a  provisional  backing  as  a  means 
of  support,  as  the  heliotype. 

3.  Those  on  which  the  film  is  used  as  a 
basis,  from  which  plates  either  in  high  or 
in  low  relief  may  be  obtained,  either  by 
etching  or  by  building  up  parts  of  the 
metal.  To  this  class  the  heliogravure, 
some  varieties  of  photozincography, 
photogravure,  and  the  various  processes 
based  on  the  use  of  the  salts  of  mer- 
cury or  copper,  &c,  belong 

4.  Those  in  which  the  film  is  used  for 
obtaining  a  mould  of  the  image  in  soft 
metal,  as  lead,  tin,  or  pewter,  from  which 
the  impressions  may  be  taken.  In  this 
class  we  have   the  Woodburytype  or 


76 


photoglyph,  and  the  photogravure  proc- 
ess of  M.  Rousselon. 

5.  A  miscellaneous  class,  which  com- 
prises many  methods,  and  great  variety 
in  treatment. 

As  the  dichromates  of  potassium  and 
of  ammonia,  and  the  sensitive  bitumen  of 
Judea,  are  the  sensitizing  agents  in  gene- 
ral use  in  the  processes  about  to  be  de- 
scribed, it  may  not  be  amiss  to  go  a 
little  into  the  general  chemistry  of  the 
operations. 

In  the  presence  of  organic  matter,  the 
bichromates  just  mentioned  become 
rather  unstable  compounds,  and  if  sub- 
jected to  the  action  of  the  light,  decom- 
position and  recomposition  begin  imme- 
diately. The  dichromate  of  potassium 
(k2  ci\  o7)  readily  parts  with  its  oxygen  and 
potassium,  giving,  with  the  aid  of  the 
organic  matter,  a  chromium,  oxide,  a 
potassium  salt,  and  a  slight  change  in  the 
molecular  construction  of  the  organic 
matter  with  a  probable  loss  of  hydrogen. 

The  image  would  then  remain  as  a 
chromium  salt  insoluble  in  water,  while 


77 


the  potassium  salt,  readily  soluble,  is 
easily  washed  out,  giving  us  the  utmost 
simplicity  in  the  process  of  development. 
The  ammonia  salts  are  very  analogous  in 
action  to  the  salts  of  potassium.  The 
bitumen  of  Judea  is  a  very  important 
agent  in  many  of  the  processes  now  in 
use,  being  especially  valuable  on  account 
of  its  great  resistance  to  the  action  of 
the  acids  used  in  the  production  of  en- 
graved plates.  It  is  readily  soluble  in 
benzole,  turpentine  and  chloroform.  After 
exposure  to  the  light  it  loses  excessive 
solubility,  and  it  is  quite  practicable  to 
dissolve  away  from  a  thin  layer  of  it,  all 
of  those  portions  which  have  not  been 
acted  upon  by  the  light.  It  seems  that 
daring  exposure  it  becomes  oxidized  to  a 
certain  extent. 

Collotype  printing  is  made  possible  for 
half  tints  by  the  peculiar  property  gene- 
rated in  the  chromatized  gelatine  for 
receiving  printer's  ink  in  direct  propor-  * 
tions  to  the  action  of  the  actinic  rays 
through  the  negative  plate,  and  it  is  also 
absorptive  or  repellent  of  water  in  a  simi- 


78 


lar  degree,  so  that  when  a  roller,  charged 
with  greasy  printer's  ink,  is  passed  over 
the  surface  of  the  film  after  the  applica- 
tion of  a  wet  sponge  the  ink  adheres  co- 
piously to  the  parts  corresponding  to 
the  deepest  shadows,  and  in  a  lesser 
degree  to  those  corresponding  to  the 
half  tints,  the  pure  whites  being  dis- 
solved out  with  water. 

In  the  autotype  and  albertype  proc- 
esses a  smooth  or  a  ground  plate  glass 
acts  as  a  support  for  the  gelatine  film 
during  development  and  printing. 

In  the  autoglyph  or  in  do -tint  a  copper 
plate  polished  and  slightly  mulled  with 
emery  powder  forms  the  backing.  In 
the  heliotype  the  gelatine  film  is  trans- 
ferred as  a  pellicle  to  a  thin  zinc  plate, 
and  then  printed  from.  None  of  these 
processes  leave  a  plate  mark  in  the  print, 
and  after  printing  the  prints  are  gener- 
ally trimmed,  mounted  and  glazed. 

In  the  autotype  and  the  autoglyph  or 
indo-tint  processes,  the  sensitive  com- 
pound consists  of  a  from  6  to  7  per  cent, 
solution  of  gelatine  in  about  equal  parts 


79 


of  alcohol  and  water,  which  after  perfect 
dissolution  is  sensitized  by  the  addition 
of  1  or  1^  per  cent,  of  ammonium  bi- 
chromate Fish  glue,  glycerine,  soluble 
glass  and  chrome  alum  are  sometimes 
added  according  to  requireniGnts.  Both 
plate  and  solution  having  been  warmed 
to  about  100°  F.,  a  rather  strong  and  very 
even  coating  is  applied,  and  the  plate 
placed  on  a  level  shelf  in  the  drying  box, 
where  it  is  left  in  a  temperature  of  from 
120°  to  130°  F.  until  thoroughly  desi- 
cated,  a  second  coating  of  the  same  mix- 
ture is  then  applied,  wmich  is  generally 
made  a  little  thinner  than  the  first  by  al- 
lowing more  of  the  excess  of  the  solution 
to  run  off  the  edges  of  the  plate,  the  lat- 
ter is  restored  to  the  drying  closet,  dried, 
cooled,  and  is  then  ready  for  printing 
under  the  negative. 

In  using  this  gelatine  film  the  progress 
of  the  printing  cannot  be  examined  as 
such  a  print  on  paper,  and  recourse  must 
be  had  to  a  photometer  as  with  the 
negative  process,  the  time  of  expos- 
ure depends  entirely  on  the  strength  of 


80 


the  light  and  the  quality  cf  the  nega- 
tive. 

Heliotype. — In  the  heliotype  process 
both  the  sensitive  compound,  and  the 
manipulations  in  the  preparation  of  the 
film  are  somewhat  different  from  those 
just  described.  Eight  parts  of  gelatine 
are  dissolved  in  100  parts  of  water,  and 
four  parts  of  potassium  bichromate  are 
added,  together  with  a  small  amount  of 
chloride  of  silver.  The  addition  of  JJ- 
per  cent,  of  glycerine  and  the  same 
amount  of  chrome  alum  is  recommended. 
The  chrome  alum  slightly  hardens  the 
film.  The  solution  being  prepared  and 
filtered,  plates  of  ground  glass  are 
rubbed  with  a  thin  solution  of  beeswax 
or  benzine,  and  leveled  accurately  on  a 
table  by  means  of  wooden  wedges  or 
screw  eyes.  The  necessary  quantity  of 
the  gelatinous  mixture  is  then  poured 
upon  the  center  of  the  plate,  1  oz.  to 
every  34  square  inches,  and  spread  with 
the  finger  to  within  J  inch  of  the  edges. 
This  may  be  done  in  day  light,  as  bi- 
chromated  gelatine  is  altogether  insensi- 


81 


tive  when  wet.  As  soon  as  the  gelatine 
has  set,  the  plates  are  removed  to  the 
drying  room,  where  they  are  placed  on 
shelves  in  a  sloping  position,  and  left  to 
dry  for  48  hours  in  a  current  of  air,  the 
temperature  averaging  80°  F.  When 
dry.  a  wet  sponge  is  passed  over  the 
edges  of  the  film,  a  knife  inserted  under 
one  corner,  and  the  pellicle,  resembling 
a  thick  sheet  of  oiled  paper,  is  pulled 
from  the  plate.  In  order  to  lessen  the  re- 
lief characteristic  of  gelatine  treated  with 
water  after  exposure  under  a  negative, 
the  film  is  placed  face — that  is,  ground 
glass  side — down  upon  boards  covered 
wTith  black  velvet,  and  their  backs  are 
then  exposed  to  diffused  light  for  about 
twenty-five  minutes,  the  proper  duration 
of  this  sunning  being  governed  by  an 
actinometer.  After  this  they  are  placed 
in  a  printing  frame  and  exposed  under  a 
negative. 

After  exposure  the  pellicle  is  ready  to 
be  transferred  to  its  final  support,  which 
is  done  by  floating  it  in  a  tank  of  clean 
water  on  a  zinc  plate  coated  with  a  solu- 


82 


tion  of  rubber  or  benzine.  A  squeegee 
is  then  passed  two  or  three  times  over 
its  surface,  and  the  plate  is,  without 
washing,  transferred  to  the  printing 
press.  The  composition  of  the  inks,  and 
their  application  to  the  cliche  are  iden- 
tical in  all  of  the  processes.  Two  inks 
are  used,  of  which  one  is  rather  stiff  and 
black,  and  is  intended  for  the  shadows 
only,  while  the  other  is  rather  thin,  and 
generally  toned  by  the  addition  of  a  little 
carmine,  rose  madder  and  cobalt,  and  is 
applied  to  the  rendering  of  the  halftones 
and  subdued  lights  of  the  picture.  The 
first  ink  is  applied  under  rather  a  strong 
pressure  with  a  leather  roller,  the  second 
by  a  light  sweep  of  a  composition  roller. 
The  processes  described  above  are  in 
use  at  the  laboratory  at  Willett's  Point, 
and  excellent  results  are  obtained  under 
the  skillful  management  of  Sergeant 
Von  Sothen  of  the  U-  S.  Corps  of  Engi- 
neers. 

Albertype. — This  process,  invented  by 
M.  Albert,  of  Munich,  is  very  similar  to 
the  one  just  described.     M.  Albert  has 


83 


brought  Ms  process  to  a  high  degree  of 
excellence,  and  furnishes  prints  in  all 
sizes,  from  card  size  up  to  sheets  20x30 
inches  in  size,  and  has  taken  as  high  as 
200  prints  from  a  single  film  in  a  day. 

A  thick  glass,  finely  polished,  is  placed 
polished  face  up,  and  covered  with  the 
following  solution : 

6  grammes  gelatine, 

300       "       dist.  water, 
5  to  6       u       bichromate  of  ammonia. 

The  gelatine  is  first  placed  for  half  an 
hour  in  cold  water  ;  it  is  then  warmed  to 
about  40°  C,  and  the  bichromate  is  added 
little  at  a  time.  To  this  liquid  is  added 
100  cubic  centimeters  of  albumen  ;  when 
the  mixture  has  cooled  to  about  25  or  30° 
C.  it  is  beaten  rapidly  and  then  filtered  in 
warm  place,  and  is  then  poured  on  the 
glass  and  placed  in  a  box  to  dry.  The 
interior  of  the  box  being  kept  at  a  tem- 
perature of  about  30°  C.  After  the  gela- 
tine is  set  the  plate  is  put  in  a  black 
cloth,  the  gelatine  next  to  the  cloth,  and 
the  glass  side  is  exposed  to  the  light  for 
5  or  10  minutes.    The  gelatine  next  to 


84 


the  plate  becomes  insoluble,  and  adheres 
to  the  plate,  which  is  now  ready  for  the 
second  coating.  The  plate  is  now 
plunged  for  half  an  hour  in  cold  water, 
and  is  then  dried  in  a  vertical  position. 
The  second  phase  of  the  proceeding 
consists  in  covering  the  first  coating  of 
gelatine  with  a  second,  composed  as  fol- 
lows : 

(a)  20  grammes  of  gelatine  softened  in 

cold  water. 
125  grammes  of  dist.  water,  cold. 

(b)  4t  grammes  of  fish  glue,  finely  di- 

vided and  softened  in 
60  grammes  of  cold  water. 

(c)  albumen  beaten  white  and  allowed  to 

settle,  and  filtered  through  a 
cloth. 

(d)  10  grammes  of  bichromate  of  potas- 

sium dissolved  in  60  grammes 
of  dist.  water ;  filter. 

(e)  5  grammes  lupuline,        )  arestir- 
3  grammes  benzine,         >•  red  12 
2  grammes  Tolu  balsam,  )  h'rs  in 

100  grammes  aqueous  alcohol  (at  8° 
Gay  Lussac). 


85 


(/')     1  gramme  nitrate  of  silver, 

30  grammes  dist.  water. 
(g)      2  grammes  bromide  cadmium, 
2  grammes  iodide  of  cadmium, 
30  grammes  water. 
Of  these  different  solutions  mix  first 
(a)  and  (&),  when  the  liquid  has  reached 
about  35°  C.  add 

of  (c)  about   6  grammes. 
"  (d)     "  36 
*t  (e)     "      4  66 

"(f)    «     U  " 

«(g)  «  45  " 
This  will  produce  a  precipitate  in  the 
mixture,  which  must  be  shaken  and  fil- 
tered into  a  flask  and  maintained  at  35°  C. 
in  temperature.  The  gelatine-covered  glass 
is  immersed  in  tepid  water  40°  C.  until 
the  water  will  flow  in  a  continuous  sheet 
over  its  surface.  It  is  then  dried  for 
half  an  hour  in  a  vertical  position,  and 
is  then  covered  with  the  prepared  mix- 
ture and  is  placed  in  a  horizontal  posi- 
tion to  dry.  Very  thin  films  are  good  for 
the  reproduction  of  line  drawings ;  thicker 
ones  are  better  for  the  half  tints.  The 


86 


dried  film  is  placed  on  the  printing 
frame  under  the  negative,  and  exposed  to 
the  light  until  the  shades  of  the  image 
are  visible  through  the  glass.  After  suf- 
ficient exposure  the  plate  is  plunged  in 
cold  water,  and  the  superfluous  potas- 
sium and  chromium  salts  are  washed  out. 
The  plate  is  then  dried  in  a  vertical  po- 
sition. Before  submitting  the  film  to  the 
printing  it  is  immersed  for  4  or  5  min- 
utes in  cold  water,  to  which  a  little  glyc- 
erine has  been  added.  It  is  wiped  off 
with  a  dampened  sponge,  and  then  rubbed 
with  a  flannel  cloth  and  a  little  oil.  The 
inking  can  then  be  proceeded  with  as  de- 
scribed above.  The  film  should  not  be 
allowed  to  become  completely  dry  during 
the  printing.  It  should  be  wiped  first 
with  a  damp  sponge,  and  then  with  a 
sponge  moistened  with  water  and  sul- 
phuric ether.  A  solution  of  fresh  fish 
glue,  bichromate  of  potassium  and  albu- 
men will  suffice  instead  of  the  abo  ve  com- 
plicated formula  as  used  by  M.  Albert. 
The  best  quality  of  gelatine  should  be 
selected.     The  proofs  obtained  by  ML 


87 


Albert  resemble  the  most  beautiful  silver 
print  photographs,  and  leave  nothing  to 
be  desired  in  the  way  of  fineness  and 
half  tints.  Of  course  extreme  care  is 
necessary  for  the  reproduction  of  first- 
class  work.  The  glass  plate  must  be 
thoroughly  cleaned  with  acid  and  dry 
cloths,  and  must  be  entirely  removed 
from  the  presence  of  dust  and  the  action 
of  the  light  in  the  dark  room. 

Phototype. — The  processes  just  de- 
scribed are  phototypic 

M.  VidaFs  phototypic  process  differs 
from  that  of  M.  Albert  in  some  of  the 
details.  The  liquid  containing  the  sensi- 
tive matter  is  formed  of 

Gelatine   90  grammes 

Water    720  " 

Isinglass   30  6i 

Water  ...........  .  360  " 

Bichromate  of  potassium  15  " 

"         "  ammonia.  15  " 

Water   360  " 

This  is  applied  as  a  second  coating 
after  the  first,  composed  of 


88 


Albumen . 
"Water  . . . 
Ammonia 


180  grammes, 


150 
100 


Bichromate  of  potassium     5       4  £ 
has  been  applied,  and  the  plate  treated  as 
in  the  process  of  M.  Albert.     After  ex- 
posure and  development  he  plunges  the 
plate  in  a  bath  of 

Water  180  grammes. 

Alum   2  " 

and  allowing  it  to  remain  for  from  5  to 
10  minutes.  It  is  then  placed  vertically 
to  dry.  The  plates  are  dampened  before 
the  inking  by  immersing  them  in  a  bath 


Glycerine. .  * » .    40  grammes 
The  glass  plate  is  then  placed  on  the 
bed  of  the  press  on  top  of  a  white  blot- 
ting paper  which  has  been  immersed  in  a 
solution  of 

Benzine . ....  100  cu.  cent. 
Caoutchouc  . .    10  grammes. 
Different  kinds  of  cylinder  presses  can 
be  used  for  taking  phototypic  impres- 


of 


Water 


100  cu.  cent. 


89 


sions,  that  is,  such  as  might  be  employed 
in  printing  from  an  engraved  plate.  A 
thin  sheet  of  caoutchouc  should  be  placed 
between  the  back  of  the  paper  and  the 
cylinder.  The  presses  generally  used 
for  phototype  printing  are  similar  to 
lithographic  presses.  The  inking  is  done 
mechanically,  and  from  a  good  plate 
from  1,000  to  1,500  prints  can  be  taken 
per  day.  I  have  gone  considerably  into 
the  details  of  these  processes, .as  they  are 
probably  the  most  important  ones  within 
the  possibilities  of  amateurs.  In  photo- 
typic  printing  with  a  strong  press  a  hard 
film  is  necessary,  else  it  will  soon  be  de- 
stroyed. The  process  of  M.  Gbernetter, 
of  Munich,  seems  to  be  the  most  satisfac- 
tory one  in  use  to-day.  The  mounting, 
varnishing  and  satining  of  phototypic 
proofs  is  readily  acquired  with  a  little 
practice.  If  printed  on  sized  paper  the 
varnishing  can  be  proceeded  with  as 
soon  as  the  printing  is  dry  ;  if  the  paper 
is  unsized  the  print  must  be  gelatined 
before  varnishing.  Dissolve  100  grammes 
of  white  gelatine  in  1,000  grammes  of 


90 


water,  and  apply  it  to  the  print  with  a 
brush.  There  is  no  process  which  lends 
itself  so  readily  to  all  kinds  of  work  as 
this.  It  is  very  usefully  employed  in  the 
illustration  of  editions  de  luxe,  and, 
thanks  to  mechanical  appliances  for 
printing,  good  prints  are  produced  very 
cheaply. 

Phototype-process  of  M.  Obernetter,  of 
Munich : 

There  are  many  varieties  of  photo- 
typic  processes,  differing  in  minor  opera- 
tions only.  The  autotype,  albertype,  and 
heliotype  processes  are  photo'typic,  and 
have  been  given  different  names  to  cover 
patents  on  details.  The  process  as  car- 
ried on  by  M.  Obernetter  gives  most  ex- 
cellent results,  and  is  very  simple  in  the- 
ory, and  the  half  tints  are  obtained  from 
the  model  to  such  a  degree  of  perfection 
as  to  have  the  appearance  of  albumen 
proofs.  The  surface  of  a  plate,  either  of 
glass  or  of  metal,  is  covered  with  a  film 
composed  of  7  parts  of  albumen,  3  parts 
of  silicate  of  soda,  and  8  parts  of  water. 
This  film  is  dried  either  in  the  air  or  by 


91 


artificial  heat.  When  dry  it  is  washed  for 
about  5  minutes  in  clean  water,  and  is 
again  placed  on  a  shelf  to  dry.  When 
dry  it  is  placed  on  a  warm  stove,  and 
when  it  has  arrived  at  a  temperature  of 
100°  it  is  covered  with  a  second  coating, 
composed  of  50  grammes  gelatine,  50 
grammes  isinglass,  and  15  grammes  bi- 
chromate of  ammonia  in  a  litre  of  water. 
As  soon  as  this  solution  is  equally  spread 
over  the  surface  of  the  plate  it  is  placed 
in  a  stove  to  dry.  When  dry  it  is  ex- 
posed under  a  negative  for  a  very  short 
time,  and  is  then  washed  in  water  for  10 
or  15  minutes  until  the  superfluous  salts 
of  chromium  and  ammonia  are  washed 
out.  As  soon  as  dry  it  is  ready  for  the 
press,  and  ordinary  lithographic  ink  can 
be  used.  It  is  a  cheap  and  rapid  process, 
and  gives  very  fine  and  very  durable 
prints. 

Photo- Zincography. — This  process  in 
its  simplest  form  is  as  follows  : '  A  zinc 
plate  of  uniform  thickness  is  carefully  pol- 
ished and  cleaned.  The  face  is  then  coated 
with  a  dilute  solution  of  bitumen  in  ben- 


92 


zole,  and  is  allowed  to  dry.  It  is  then 
exposed  under  a  negative.  After  suffi- 
cient exposure  the  soluble  parts  are 
washed  out  with  turpentine,  leaving  the 
bare  metal  on  the  lines  not  acted  on  by 
the  light.  The  plate  is  then  slightly 
etched,  to  give  the  bitumen  film  a  little 
greater  relief ;  it  is  then  printed  from,  as 
in  lithography.  Major  de  La  No'ie  made 
the  following  alterations  in  the  process  : 
The  plate  is  coated  as  described  above, 
but  is  exposed  under  a  drawing  made  on 
tracing  paper.  A  longer  time  is  neces- 
sary in  the  exposure,  as  the  paper  slight- 
ly impedes  the  passage  of  the  actinic 
rays.  After  exposure  the  picture  is  de- 
veloped with  turpentine,  as  above,  and 
the  plate  is  etched  with  a  5  per  cent,  so- 
lution of  nitric  acid  for  from  ^  to  f  of  a 
minute.  It  is  then  washed  with  wrater 
and  the  remainder  of  the  bitumen  is 
washed  off  with  benzole,  and  the  plate  is 
thoroughly  cleaned.  It  is  again  coated 
with  the  bitumen  solution,  and  the  entire 
face  exposed  to  the  light.  The  etched 
portions  become  filled  with  the  insoluble 


93 


solution,  and  the  other  portions  must  be 
removed.  This  is  done  mechanically 
by  scouring  the  plate  with  a  stick  of  hard- 
wood charcoal,  ground  to  a  beveled  edge 
and  moistened  with  oil.  The  etched 
parts  still  retain  the  bitumen,  and  the 
plate  can  be  printed  from  as  in  lithog- 
raphy. 

The  chemical  process  is  as  follows : 
The  second  coating  of  bitumen  is  worked 
with  a  roller,  and  exposed  to  the  light. 
After  exposure  the  soluble  parts,  viz., 
those  that  have  taken  the  ink,  are  washed 
out  with  turpentine;  the  etched  parts, 
being  lower  than  the  others,  have  re- 
ceived no  ink.  The  plate  is  washed  and 
printed  from  as  before  described. 

Calbon  Pkixts. — The  carbon  process 
is  an  important  one,  and  is  extensively 
used,  and  I  will  go  somewhat  into  details 
in  describing  it.  A  sheet  of  paper  cov- 
ered with  a  gelatine  "  couche  "  and  color- 
ing matter  (generally  India  ink,  from 
which  the  process  derives  its  name)  con- 
stitutes carbon  paper.  It  is  sensitized 
by  immersion  in  a  solution  of  bichromate 


94 


of  potassium,  and  is  suspended  in  a  dark 
and  well- aired  chamber  to  dry.  It  is 
then  exposed  under  the  negative.  As 
the  progress  of  the  image  is  not  visible 
a  photometer  must  be  used  to  regulate 
the  time  of  exposure. 

Two  ways  now  present  themselves  for 
obtaining  the  image. 

1st.  By  simple  transfer,  a  process  of 
wonderful  simplicity,  but  which  gives 
the  image  reversed,  as  regards  right  and 
left. 

2d.  Double  transfer,  which  gives  the 
image  in  a  correct  form,  but  which  is 
more  complicated  in  operation. 

Sensitizing  of  the  Paper. — This  opera- 
tion is  very  simple,  but  of  great  impor- 
tance, and  the  success  of  the  subsequent 
operations  depends  upon  its  regularity. 
The  sensitizing  should  be  done  in  a  dark 
room,  with  yellow  or  red  lights ;  the  cu- 
vette, or  dish  containing  the  mixture 
should  be  of  wood  lined  with  glass,  as 
the  bichromate  readily  attacks  wood  or 
gutta-percha.  Mix  the  following  solu- 
tion : 


95 


Water  .   10  liters, 

Bichromate  of  potassium .  200  grammes, 
Carbonate  of  ammonia.  .  10  " 
The  ordinary  commercial  bichromate  may 
be  used,  but  it  should  be  finely  pulver- 
ized. The  mixture  is  poured  into  a  flask, 
thoroughly  shaken  until  the  bichromate 
is  dissolved ;  it  is  then  filtered  and 
poured  into  the  cuvette.  One  bath  of 
bichromate  should  not  be  used  for  sensi- 
tizing too  many  sheets  of  the  paper,  as  it  is 
poor  economy  to  compromise  the  results 
in  order  to  save  so  cheap  a  mixture.  Be- 
fore immersing  the  paper  in  the  bath 
dust  it  carefully.  Submerge  the  paper 
in  the  mixture,  couche  uppermost,  and 
keep  the  liquid  moving  by  rocking  the 
cuvette.  Keep  the  paper  immersed  for 
about  3  minutes,  then  remove  it  and  re- 
immerse  it  for  about  one  minute,  the 
couche  down,  to  work  the  adhering  bub- 
bles from  the  back.  After  withdrawing, 
place  it  face  down  on  an  inclined  glass  plate? 
and  with  a  scraper  work  on  the  back,  from 
the  center  towards  the  edges,  until  all  of 
the  excess  of  liquid  is  forced  out ;  then 


96 


detach  the  sheet  from  the  glass  and  sus- 
pend it  to  dry.  The  bath  should  be 
kept  at  a  temperature  of  about  15°  C. 
Eubber  gloves  should  be  used  while 
working  with  the  bichromate,  as  it  is  a 
poison  which  acts  .  by  absorption,  and 
should  be  handled  very  carefully.  If  we 
wish  to  produce  vigorous  images  with 
light  negatives,  the  paper  must  be  used 
the  next  morning  after  drying ;  but  if 
the  negatives  are  strong  it  is  better  to 
wait  48  hours  after  the  sensitizing  before 
using  it.  Negatives  for  carbon  prints 
ought  to  be  a  little  more  intense  than  for 
albumen  paper.  The  edges  of  the  nega- 
tive must  be  covered  with  yellow  paper, 
so  as  to  limit  the  cliche  to  the  part  to  be 
reproduced,  and  the  carbon  paper  must 
be  cut  so  that  its  edges  shall  not  pass 
the  edges  of  the  yellow  paper  which  pro- 
tects the  edges  of  the  cliche ;  it  is  then 
placed  in  the  printing  frame  and  ex- 
posed, and  the  time  regulated  by  a 
photometer.  The  impression  on  carbon 
paper  continues  even  after  the  action  of 
the  light  has  ceased;  this  is  an  import- 


97  jgW^fa 

ant  point  to  remember.  Wye  now  come 
to  the  development  and  the  simple  trans- 
fer. Simple  transfer  paper  iss£vr.epared 
in  rolls  exactly  like  carbon  paper.  It  is 
covered  with  a  couche  of  gelatine  and 
chrome  alum.  Before  using  this  paper 
it  is  well  to  mark  the  reverse  side  of  it 
with  a  crayon,  so  it  will  be  easily  recog- 
nized in  the  subsequent  operations- 
Transfer. — The  transfer  paper  having 
been  cut  to  dimensions  a  little  greater 
than  the  proof  it  is  immersed  for  two  or 
three  minutes  in  cold  water ;  it  is  then 
placed  on  a  flat  glass,  or  on  a  marble 
block,  face  up.  The  carbon  proof  is  then 
immersed  in  cold  water,  buck  up,  rub- 
bing it  with  the  hand  so  as  to  force  out 
air  bubbles.  It  is  then  placed  on  top  of 
the  transfer  paper,  face  down,  and  the 
back  is  rubbed  quickly  and  strongly  with 
a  scraper  until  the  surfaces  unite  and 
the  air  bubbles  and  excess  of  water  are 
forced  out ;  a  dry  sponge  is  a]so  passed 
over  the  back  and  the  edges  of  the 
paper. 

Development. — One  ought   never  to 


98 


proceed  to  the  development  before  the 
bichromate  has  taken  hold  of  the  trans- 
fer paper,  which  ought  to  become  yellow 
in  its  texture,  and  which  can  be  observed 
by  looking  at  the  underside.  The  devel- 
opment can  be  made  in  full  light,  indeed 
it  ought  to  be  done  in  the  light,  as  it  is 
necessary  to  judge  of  the  condition  of 
the  image  at  all  stages  of  development. 
The  transfer  paper,  supporting  the  carbon 
paper,  is  now  put  into  water  at  about  30° 
C,  the  cuvette  being  constantly  shaken 
to  favor  the  absorption  of  the  warm 
water.  After  a  few  minutes  dark-colored 
veins  are  seen  on  the  edges  of  the  proof, 
and  soon  the  edges  show  a  tendency  to 
separate.  Take  the  carbon  paper  by  a 
corner  and  s]owly  and  carefully  detach 
it  from  the  transfer  paper.  The  image 
will  be  seen  transferred  to  the  paper, 
which  must  be  left  in  the  warm  water  un- 
til the  surplus  coloring  matter  is  washed 
out.  The  temperature  of  the  water 
should  be  raised  to  about  40°  C.  by  the 
addition  of  hot  water.  The  image  is 
formed  by  the  gelatine  in  relief,  and  is 


99 


very  fragile  ;  it  should  be  immersed  for 
10  minutes  in  the  following  solution : 


This  bath  should  be  freshly  made  and 
filtered.  The  proofs  are  then  immersed 
in  water  for  an  hour  and  are  hung  up  1 1 
dry.  After  drying  the  proof  is  retouche:!, 
mounted,  put.  through  the  satin  press, 
and  varnished.  Once  dry,  the  imagj  is 
of  extreme  solidity  and  durability. 

Double  Tkansfer.  —  A  flexible  support  i  s 
especially  prepared  with  the  aid  of  simple 
transfer  paper,  which  is  covered  with  a 
varnish  of  (wax,  1  part ;  warm  benzine, 
5  parts).  The  paper  appears  brilliant  on 
the  side  which  is  to  receive  the  transfer 
provisionally. 

The  operations  for  the  first  transfer 
are  in  every  way  identical  with  those  just 
described.  When  the  image  is  raised 
from  the  water,  after  the  development,  it 
is  placed  on  a  thick  glass,  face  up,  and 
the  operator  immediately  proceeds  to 
the  second  transfer.     The  double  trans- 


Water   

Pulverized  alum. 


5  liters, 

250  grammes. 


100 


fer  paper  is  covered  with  a  couche  of 
gelatine,  rendered  half  insoluble  by 
chrome  alum.  The  paper  is  cut  of  a 
little  larger  dimension  than  the  image, 
and  is  immersed  in  water  at  a  temperature 
of  40°  CL  When  the  gelatine  is  a  little 
softened  remove  the  paper  from  the 
water,  and  place  it  carefully  on  top  of 
the  carbon  image ;  cover  the  back  with 
a  sheet  of  caoutchouc,  and  with  a  scraper 
work  out  the  air  bubbles  and  super- 
fluous moisture,  and  continue  the  opera- 
tion until  the  two  papers  form  a  homo- 
geneous sheet.  Suspend  this  to  dry  in  a 
chamber  well  aired  and  lightly  warmed  ; 
when  dry  insert  a  knife  edge  between 
the  two  papers,  and  detach  them  from 
one  another,  which  is  easily  done.  The 
image  will  be  found  on  the  paper  which 
is  to  receive  the  final  transfer ;  it  is 
mounted,  retouched  and  varnished. 

Double  Transfer  with  the  aid  of 
Glass. — Polished  glass  of  from  4  to  5 
millimeters  in  thickness  is  generally  used 
for  this  purpose,  and  has  this  advantage: 
The  condition  of  the  image  and  the  state 


101 


of  the  development  can  be  observed 
through  the  glass*  The  glass  is  first 
thoroughly  cleaned,  and  is  coated  with 

Yellow  wax .  <, . . .      1  gramme, 
Good  benzine. .  .  150  cuk  cent, 

which  is  rubbed  on  the  glass  with  a  flan- 
nel rag  and  allowed  to  dry.  After  dry- 
ing, the  surface  may  be  polished  by  rub- 
bing it  lightly  with  a  dry  flannel  cloth* 
The  coating  of  collodion,  made  as  fol- 
lows : 

Ether   ^  liter, 

Alcohol  i  " 

Pyroxyline  5  grammes, 

is  then  poured  on  the  glass  as  prescribed 
in  photography.  The  glass  is  dried,  is 
well  washed,  and  placed  flat  on  a  table, 
and  the  first  transfer  is  made  as  described 
for  the  transfer  paper.  A  sheet  of 
caoutchouc  should  be  interposed  between 
the  scraper  and  the  carbon  paper.  In 
about  10  minutes  after  the  transfer,  one 
can  proceed  to  the  development,  After 
the  development  the  glass  is  placed  for 
about  five  minutes  in  the  alum  bath, 


102 


which  hardens  the  couehe.  After  it  has 
dried  make  a  mixture  of 


immerse  the  proof  in  it  for  3  or  4  min- 
utes. The  alcohol  takes  the  water  from 
the  gelatine  and  lowers  the  relief  Then 
apply  the  double  transfer  paper,  and  pro- 
ceed as  prescribed  for  the  double  trans- 
fer with  the  aid  of  paper.  The  retouch- 
ing can  be  done  on  the  glass  before  the 
second  transfer,  if  desired,  and  should  be 
done  with  a  mixture  of  red  and  black  oil 
(tube)  colors.  If  certain  parts  are  want- 
ing they  can  be  put  in  with  a.  stumpf  and 
a  rather  dry  mixture  of  lamp  black  and 
madder  lake ;  the  satin  finish  is  added 
as  prescribed  for  albumen  prints.  Car- 
bon prints  are  very  durable,  and  can  be 
made  so  as  to  stand  comparison  with 
the  best  silver  prints.  It  is  best  for  be- 
ginners to  work  with  the  single  transfer 
until  some  of  the  difficulties  of  the  proc- 
ess are  thoroughly  mastered.  The  rough 
prints  obtained  by  this-  process  have 


Alcohol 
Water . 


103 

much  the  appearance  of  phototypes. 
Beautiful  transparencies  are  also  made 
on  glass  by  this  process. 

WoODBURYTYPE,  OR  PHOTOGLYPH.  This 

is  an  exceedingly  ingenious  process  of 
obtaining  a  metallic  mould  from  a  gela- 
tine film,  from  which  any  number  of 
copies  may  be  printed.  Potassium  bi- 
chromate is  mixed  with  gelatine,  giving  a 
highly  sensitive  mixture.  A  thick  film 
of  this,  resting  on  collodion,  is  exposed 
under  a  negative  to  a  strong  light,  the 
collodion  side  being  placed  next  to  the 
negative ;  the  usual  action  takes  place ; 
the  parts  remaining  soluble  are  washed 
out  with  warm  water,  leaving  the  darks 
of  the  picture  wonderfully  strong  and 
hard.  A  sheet  of  soft  metal,  generally 
lead,  is  placed  on  this  film  and  subjected 
to  very  strong  pressure.  On  removal,  a 
beautiful  mould  of  the  picture  is  found 
in  the  lead,  the  dark  parts  in  intaglio,  the 
lights  in  relief.  A  peculiar  kind  of  gela- 
tinous ink,  to  which  permanent  dye  or  fine 
pigment  may  be  added,  is  now  poured 
on  the  mould,  and  the  p>aper  on  which 


104 


the  picture  is  to  be  printed  is  placed  on 
it,  and  strong*  pressure  is  brought  to 
bear  over  the  entire  surface.  This 
forces  the  gelatinous  ink  out  of  the  lights 
which  are  in  relief,  and  gives  the  half 
tones  and  darks  by  the  varying  thick- 
nesses of  the  gelatinous  ink.  The  press- 
ure must  be  maintained  for  a  few  minutes, 
to  allow  the  ink  to  set  on  the  paper ;  the 
paper  is  then  immersed  in  a  solution  of 
alum,  which  renders  the  picture  insoluble. 
The  pictures  made  by  this  process  are 
good,  and  wonderfully  cheap.  It  can 
work  with  any  color. 

The  stannotype  is  the  name  given  to 
the  improved  process  of  M.  Woodbury. 
He  makes  use  of  a  thin  plate,  tin,  for  the 
formation  of  the  mould.  His  first  im- 
jDrovement  was  the  substitution  of  a  fine 
tin  plate  for  the  leaden  mould.  The 
plate  was  fixed  on  the  film  and  the  back 
was  strengthened  by  electrotypy.  The 
prints  were  taken  from  the  mould  in  ink 
composed  of 

Gelatine   1  part, 

Water   5  or  6  parts, 


105 


Dark  color 
A  little  red 


at  pleasure, 
to  give  tone. 


He  has  endeavored,  however,  to  still  fur- 
ther simplify  his  process  by  using  a  posi- 
tive, from  which  a  negative  relief  is 
formed.  The  fine  tin  is  forced  on  this, 
and  is  made  to  adhere  to  the  film  by  first 
giving  it  alight  coating  with  caoutchouc. 
It  is  then  only  necessary  to  put  the 
mould  directly  under  the  press  and  print 
from  it  without  any  further  treatment. 
For  fixing  he  uses  the  following  solu- 
tion : 

Alum   1  part, 

Water   50  parts. 

Photogravure.' — The  novelty  and  the 
secret  of  the  photogravure  consists  in  the 
particular  means  adopted  for  obtaining 
immediately  in  the  gelatine  the  grain  nec- 
essary to  an  engraving.  To  accomplish 
this  M.  Rousselon  (for  some  time  con- 
nected with  the  house  of  Goupiland  Co.) 
incorporated  in  the  gelatine  a  substance 
which  produced  this  grain  under  the 
influence  of  the  light,  and  in  proportion 


106 


to  the  strength  and  duration  of  the  light. 
By  the  Woodbury  process  this  grain  is 
reproduced  in  a  leaden  mould,  and  by 
the  use  of  electrotypy  a  plate  is  obtained 
which  is  printed  from  as  a  copper  plate 
engraving.  A  great  deal  depends  on  the 
skill  of  the  manipulator,  and  with  the  as- 
sistance of  the  burin  in  touching  up  weak 
parts  beautiful  plates  are  produced.  The 
process  as  now  applied  by  M.  Rousselon 
is  very  analogous  to  that  used  by  M. 
Placet  in  the  preparation  of  plates  for 
heliogravures.  The  light  is  made  to  act 
through  a  negative  on  a  bichromated  gel- 
atine film ;  the  film  is  then  immersed  in 
water  or  in  some  liquid  containing  a  con- 
tracting substance.  The  insoluble  por- 
tions, viz.,  those  acted  upon  by  the  light, 
cannot,  like  those  surrounding  them,  ab- 
sorb water,  and  remain  united  ;  they  are 
raised  up  by  the  action  of  the  water  on 
the  adjacent  susceptible  parts ;  these 
swell  out,  and  there  results  from  this  a 
contraction  more  or  less  strong  accurate- 
ly following  the  action  of  the  light. 
There  results  from  this  a  roughened  sur- 


107 


face,  which,  absent  in  the  lights,  extends 
gradually  through  all  the  tones  up  to  the 
strong  darks.  This  film  is  dried  and 
separated  from  its  provisional  backing. 
It  is  submitted  to  strong  pressure  againt 
a  thin  sheet  of  tin  or  pewter,  from  which 
an  electrotype  is  taken  ;  this  is  touched 
up  by  skilled  hands,  and  magnificent 
prints  are  obtained  from  it. 

Another  process,  never  made  public,  is 
believed  to  consist  substantially  of  the 
following  operations  :  A  phototypic  proof 
is  transferred  to  a  copper  plate  with 
sized  India  paper.  It  is  then  sprinkled 
with  bitumen  powder,  so  as  to  well  cover 
the  ink  of  the  transfer  ;  it  is  then  etched 
with  the  per-chloride  of  iron,  and  gives 
an  engraved  copper  plate  with  all  of  the 
reliefs  and  depressions  of  the  original. 

This  last  is  pure  chemical  engraving, 
and  as  such  is  more  subject  to  accidents 
than  the  mere  mechanical  one  of  M. 
Eousselon.  This  latter  is  the  prince  of 
"  processes,"  and  the  artistic  reproduc- 
tions exhibited  by  Messrs.  Goupil  &  Co. 
have,  to  say  the  least,  never  been  sur- 


108 


passed.  Some  chemical  substance  is 
added  to  the  bichromated  gelatine  which 
gives  to  it,  after  exposure,  development 
and  drying,  a^grain  more  or  less  marked 
following  the  strength  of  the  shades  in 
the  picture.  The  remainder  of  the  proc- 
ess is  purely  mechanical  and  is  thorough- 
ly understood,  and  success  is  assured. 
After  electrotyping,  the  plate  is  thor- 
oughly cleaned  and  proven,  and  re- 
touched with  the  burin,  and  the  result  is 
a  finely-grained  engraved  plate,  from 
which  beautiful  impressions  are  obtained, 
and  which  give  even  the  details  of  the 
brush  marks  of  the  artist.  The  photo- 
gravure process  of  Major  Waterhouse  ar- 
rives at  similar  results.  While  the  image 
formed  by  the  gelatine  is  still  moist  he 
covers  the  surface  with  finely-divided 
sand,  which  has  been  covered  with  wax 
to  prevent  it  from  being  retained  by  the 
gelatine  after  the  development.  The 
granulations  produced  by  the  sand  are 
aiore  or  less  deep,  following  the  relief  of 
bhe  image.  After  the  gelatine  is  dry  the 
image  is  carefully  cleaned  with  a  brush* 


109 


and  all  the  sand  removed,  leaving  the 
grain  marks  in  the  gelatine.  A  mould  of 
tje  surface  is  then  taken,  and  this  is  elec- 
trotyped  and  retouched. 

Photogravure  Garnier.  another  process, 
the  details  of  which  have  not  been  given 
to  the  public,  has  been  invented  by  M. 
Garnier,  and  is  believed  to  be  as  follows : 
A  copper  plate  is  covered  with  a  film 
formed  by  dissolving  sugar,  gum,  albu- 
men in  water.  This  is  sensitized  by  the 
addition  of  the  following  solution  : 

Sugar   2  grammes, 

Bichromate  of  ammonia    1  " 
Water   14 

This  is  exposed  to  the  light  under  a  posi- 
tive. The  hygroscopic  properties  of  the 
parts  not  acted  upon  by  the  light  permit 
the  adherence  of  finely-powdered  bitu- 
men, which  is  sprinkled  over  the  surface. 
The  plate  is  then  placed  on  a  grating 
and  heated  until  a  faint  iridescence  is 
visible  on  the  upper  edge  of  the  plate ; 
the  plate  is  then  etched  with  the  per- 
chloride  of  iron,  which  eats  out  only  the 


110 


parts  not  protected  by  the  powdered  bit- 
umen. For  delicately  graded  half  tints 
he  repeats  the  process  three  times,  using 
carefully-prepared  reference  points,  stop- 
ping out  the  biting  at  pleasure.  No  re- 
touching is  necessary,  according  to  the 
inventor,  but  an  intelligent  touch  is  al-  - 
ways  of  value. 

Heliographie  and  the  Heliogravure. — 
The  bitumen  of  Judea  is  generally  used 
as  the  sensitive  agent  in  heliographie 
processes.  It  should  be  of  an  especial 
quality.  There  are  different  substances 
of  this  nature,  but  the  following  solution 
is  found  to  give  the  greatest  resistance  to 
the  biting  acid : 

Bitumen   3  to  5  grammes- 

Anhydrous  benzine .  100  " 
Essence  of  lemon . .     2  to  5  drops. 

This  mixture  is  poured  on  the  metal  as 
collodion  is  poured  on  glass.  It  is  al- 
lowed to  dry  and  is  then  exposed  under 
the  negative.  The  exposure  complete d? 
the  insoluble  parts  are  washed  out  with 
essence  of  lavender  or  essence  of  turpen- 


Ill 


tine,  and  the  plate  is  subjected  to  the  ac- 
tion of  the  acid .  the  naked  parts,  or  the 
bare  metal  corresponding  to  the  lights  of 
the  drawing,  are  "bitten"  at  the  pleasure 
of  the  operator,  and  upon  this  the  beauty 
of  the  work  largely  depends.  After  the 
first  biting5  which  is  continued  until  the  en- 
graved parts  are  appreciable  to  the  touch, 
the  plate  is  placed  on  a  lithographic 
press  and  coated  with  an  inking  of  grey 
varnish,  which  naturally  adheres  only  to 
the  parts  covered  with  the  bitumen  and 
already  in  relief.  The  plate  is  then 
warmed,  and  the  varnish  flows  to  the 
edges  of  the  relief  and  gives  an  additional 
protection  against  the  acid.  A  new  biting 
takes  place,  and  these  same  operations 
are  continued  until  the  operator  judges 
the  biting  completed  the  bitumen  is  re- 
moved, the  plate  cleaned,  the  lines 
touched  up  with  the  burin,  and  the  plate 
is  ready  for  the  press.  During  the  suc- 
cessive operations  the  grey  varnish,  if 
placed  artistically  will  stop  out  the  action 
of  the  acid  so  as  to  give  an  exact  repro- 
duction of  the  original.     The  oj>erations 


112 


are  difficulty  but  do  not  compare  with  the 
difficulty  of  producing  an  engraved  plate 
with  the  burin.  By  eleetrotyping,  the 
converse  of  the  plate  may  be  obtained, 
making  the  process  available  for  the  pro- 
duction of  plates  either  in  high  or  in  low 
relief. 

The  bichromated  gelatine  film  is  used 
in  a  similar  manner.  After  exposure  the 
film  is  immersed  in  cold  water,  which 
causes  the  soluble  portions  of  the  gela- 
tine to  swell  out  and  form  an  image  in 
relief ;  a  plaster  cast  of  this  is  taken,  and 
this  is  in  turn  electrotyped.  The  results 
of  this  process  are  not  particularly  good ; 
it  is  available  for  line  work  only,  and 
the  swelling  of  the  gelatine  cannot  be  re- 
lied upon  for  uniformity  in  relief. 

The  invention  and  perfection  of  the 
processes  for  the  production  of  helio- 
graphic  plates  is  due  to  Scamoni,  of  St. 
Petersburg.  With  the  assistance  of  elec- 
trotypy  he  produced  excellent  plates  in 
high  relief,  a  manifest  advantage  in  the 
industrial  arts,  as  engraved  plates  require 
a  special   paper>  strong  pressure,  and 


113 


more  time  for  each  impression,  whereas, 
plates  in  relief  can  be  printed  from  in  the 
rapid  steam  press  used  in  typographic 
printing,  and  a  much  cheaper  paper  can 
be  used.  Of  course  this  necessitates  the 
sacrifice  of  a  little  of  the  fineness  of  the 
work  to  rapidity  and  economy.  The 
plates  are  covered  either  with  the  mix- 
ture of  gelatine  and  potass-dichromate  or 
with  the  sensitive  bitumen  of  Judea ; 
they  are  exposed  under  a  positive  ;  they 
are  then  etched,  which  gives  an  engraved 
plate,  and  by  electro  typing  this  we  get 
a  plate  in  relief  which  can  be  printed 
from  on  an  ordinary  press.  This  was  the 
process  as  invented  by  the  Austrian, 
Pretsch,  some  years  ago.  Scamoni 
made  the  following  changes :  He  ob- 
served that  an  ordinary  photographic 
negative  appears  in  relief,  the  transpa- 
rent places — -shadows — being  hp.  basso, 
and  the  lights  in  alto  relievo ;  this  relief 
is  very  faint.  He  increased  it  by  treat- 
ing the  freshly  developed  image  with  py- 
rogallic  acid  and  a  solution  of  silver,  and 
augmented  it  by  a  further  treatment  with 


114 


chloride  of  mercury  and  iodide  of  potas- 
sium. A  relief  was  thus  ultimately  ob- 
tained equal  to  the  depth  of  the  incisions 
in  an  engraved  copper  plate  ;  by  treating 
a  positive  in  this  manner  all  the  means 
are  at  hand  for  obtaining  an  engraved 
plate.  The  relief-like  photographic 
image  is  electrotyped,  which  gives  low 
relief  where  the  positive  is  in  high  re- 
lief, viz.,  in  the  darks  of  the  original 
drawing,  and  we  have  an  engraved  cop- 
per plate.  Most  excellent  maps  can  be 
produced  by  this  process,  with  the  origi- 
nal either  enlarged  or  diminished. 

Scanioni  reduced  a  page  of  an  illustrated 
journal  to  a  square  inch,  and  the  words 
could  be  plainly  distinguished  with  the 
aid  of  a  microscope.  It  is  very  probable 
that  the  beautiful  maps  of  the  Wheeler 
Survey  were  made  by  some  modification 
of  this  process,  which  the  Austrian  Gov- 
ernment declines  to  make  public. 

Aquatinte. — This  is  a  species  of  en- 
graving with  a  peculiarly-prepared  grain 
A  plate  of  copper  is  first  covered  with  a 
special  gray  varnish;  the   drawing  is 


115 


made  on  this  in  outline,  and,  as  in  etch- 
ing, the  bare  parts  of  the  metal  are  a  bit- 
ten in  "  with  acid.  The  varnish  is  then 
removed,  the  plate  is  cleaned  and  is 
placed  in  the  graining  box,  which  con- 
sists of  a  case  in  which,  by  mechanical 
means,  a  cloud  of  resinous  powder  can  be 
raised.  The  powder  is  put  in  motion, 
and  at  an  opportune  moment  the  plate  is 
placed  in  the  box.  A  grain  is  thus  de- 
posited on  the  surface  of  the  plate,  and 
this  grain  can  be  regulated  by  the  time 
the  plate  is  allowed  to  remain  in  the  box. 
The  operation  can  be  renewed  until  the 
grain  is  more  or  less  thick.  The  plate  is 
then  submitted  to  gentle  warmth,  which 
softens  the  resin  and  makes  it  adhere  to 
the  plate.  When  the  desired  "grainage" 
has  been  obtained  the  parts  to  remain 
white  are  covered  with  the  gray  varnish, 
and  the  biting  acid  is  poured  on  the  plate. 
It  attacks  only  the  places  not  covered  with 
the  resin  nor  with  the  varnish.  By  suc- 
cessive ':  bitings  v  and  coatings  with  var- 
nish, the  plate  may  be  etched  at  the 
pleasure  of  the  engraver,  and  the  results 


116 


are  more  or  less  beautiful,  depending 
upon  his  skill. 

A  number  of  different  processes  have 
been  invented  by  French  scientists,  based 
upon  metallic  precipitates  and  on  the  af- 
finities of  acids  for  different  metals.  For 
example,  a  drawing  made  on  zinc,  with 
an  ink  formed  of  a  salt  of  copper,  permits 
the  formation  of  a  plate  in  relief  by  the 
action  of  azotic  acid,  the  copper,  in  this 
case,  playing  the  role  of  a  protecting  var- 
nish ;  or,  we  might  use  a  salt  of  mercury 
for  copper,  a  salt  of  gold  for  silver,  &c, 
and  engrave  with  an  appropriate  acid. 

The  following  process  has  also  been 
used  :  A  plate  of  copper  is  silver  plated ; 
the  drawing  is  made  on  the  silvered  sur- 
face, or,  better,  is  transferred  to  it,  as, 
for  instance,  a  drawing  in  ordinary  litho- 
graphic ink.  With  the  assistance  of  an 
electric  battery  a  light  coating  of  iron  is 
formed  on  the  surface  of  the  plate,  the 
deposit  occurring  only  on  the  parts  not 
covered  with  the  ink.  The  ink  is  washed 
off  with  turpentine  or  benzine.  The 
whites  of  the  drawing  are  now  repre- 


117 


sented  by  the  iron,  and  the  darks  by 
the  pure  silver.  The  ammoniacal  sul- 
phate of  mercury  is  poured  on  the  plate, 
and  after  the  excess  of  the  salt  is 
brushed  off  the  metal  is  seen  in  relief 
in  all  the  parts  previously  covered  with 
the  lithographic  ink.  It  is  electrotyped, 
and  we  have  an  engraved  copper  plate. 
These  processes  are  of  doubtful  value 
now,  but  they  serve  to  illustrate  the 
many  resources  that  have  been  discovered 
and  utilized  by  scientific  men  in  the  re- 
productions of  drawings  of  various  kinds. 
The  ones  just  described  were  invented  in 
1864,  and  are  quite  modern. 

To  sum  up,  it  is  well  known  that  an 
amalgam  of  mercury  with  another  metal 
repulses  the  greasy  ink  when  the  roller 
is  passed  over  it,  and  the  black  ink  ad- 
heres only  to  the  naked  metal.  If  then, 
we  trace  on,  or  transfer,  a  drawing  in 
mercuric  ink  to  a  zinc  plate  well  polished, 
it  will  appear  in  brilliant  white  lines  on 
the  gray  back  ground  of  the  zinc.  To 
obtain  a  plate  in  high  relief  it  is  only 
necessary  to  plunge  the  plate,  without 


118 


the  application  of  varnish  or  any 
stop,  into  the  acid  bath  composed  of  1 00 
parts  water  to  2  parts  of  nitric  acid. 
The  biting  takes  place  very  rapidly,  and 
the  lines  traced  with  the  mercury  soon 
stand  out  in  relief,  and  can  be  printed 
from  in  a  lithographic  press.  If,  instead 
of  plunging  the  plate  into  a  nitric  acid 
bath,  we  use  a  dilute  solution  of  hydro- 
chloric  acid,  the  reverse  obtains,  the 
lines  are  eaten  away  and  we  obtain  an 
engraved  plate  in  low  relief.  So  far  we 
have  included  only  line  drawings.  To 
produce  half  tints  the  drawing  is  made 
on  a  very  dense  paper,  and  is  transferred 
to  the  zinc  plate  by  strong  pressure  for 
about  two  hours.  By  pulling  off  the 
paper  the  drawing  will  be  seen  in  clean, 
white  amalgam  on  the  gray  surface,  and 
may  be  treated  as  before.  An  ink,  con- 
taining sugar,  gum,  &c,  in  solution,  may 
be  used  on  the  drawing  ;  on  powdering 
this  with  a  fine  mercurial  powder  the 
same  effects  may  be  obtained ;  the  bi- 
iodide  of  mercury  is  the  salt  generally 
used.    It  is  thought  that  these  processes 


119 


are  destined  to  become  of  great  value  in 
the  graphic  arts.  The  salts  of  mercury 
are  violent  poisons,  and  must  be  handled 
carefully :  white  of  egg,  sulphur-water 
and  milk  are  antidotes. 

Similigkavure. — M.  C.  Petit  has  in- 
vented a  process  of  engraving,  having  for 
its  object  the  changing  of  the  half  tints 
of  a  photographic  proof  into  line  prints 
for  the  production  of  typographic  blocks. 
The  negative  is  placed  over  a  bichro- 
mated  gelatine  film,  and  the  image  is  de- 
veloped as  in  the  autotype.  A  plastic 
material,  such  as  hardened  white  wax,  is 
pressed  on  the  film,  giving  a  counter 
proof  of  the  gelatine ;  this  is  placed  under 
a  line-drawing  machine  with  a  V-shaped 
cutting  edge,  and  the  wax  is  ruled  with 
parallel  lines,  the  depth  being  regulated 
by  the  operator.  The  surface  of  the  wax 
having  been  covered  with  plumbago  just 
after  its  removal  from  the  gelatine,  we 
now  h^ve  white  lines  on  a  black  back- 
ground, the  darks  having  been  engraved 
more  or  less  in  proportion  to  the  relief. 
From  this  wax  mould  a  photographic 


120 


cliche  is  formed,  and  from  this  we  get  a 
typographic  cliche,  as  explained  for  other 
processes. 

Gillotage  .  — M.  Gillot  has  invented  a 
process  for  obtaining  a  line  negative, 
from  which  excellent  typographic  blocks 
can  be  produced.  He  takes  a  strong 
paper  and  covers  it  with  a  white  glazing ; 
then,  with  a  prepared  plate,  he  prints  a 
series  of  parallel  dark  lines  on  the  glazed 
paper,  giving  about  three  lines  to  the 
millimeter.  A  steel  plate  is  then  put  un- 
der a  line-engraving  machine,  and  a  series 
of  parallel  lines,  corresponding  to  those 
on  the  paper,  are  cut  into  the  plate  to 
the  depth  of  about  ^  of  a  millimeter. 
The  paper  is  then  pressed  on  this  plate 
so  as  to  give  two  series  of  lines  at  right 
angles  with  each  other,  one  series  being 
the  dark  lines  drawn  on  the  paper,  the 
other,  the  fine  creases  formed  by  the 
relief  parts  of  the  plate.  The  paper  is 
now  ready  for  the  drawing;  the  pure 
whites  are  smoothed  down  with  a  scraper, 
so  as  to  make  the  creases  disappear,  and 
the  dark  lines  are  erased ;  for  the  half 


121 


tints  lie  relies  on  the  handling  of  the 
crayon,  for  the  full  darks  the  creases 
are  filled  with  India  ink;  a  negative  is 
taken  from  this.  A  zinc  plate  is  cov- 
ered with  a  thin  coating  of  the  sensitive 
bitumen,  and  from  this  especially  pre- 
pared negative,  a  relief  plate  is  obtained, 
with  the  half  tones  excellently  well  ren  - 
dered,  as  the  negative  gives  them  in  se- 
ries of  lines,  which  are  much  more  readi- 
ly handled  and  transferred  than  the  or- 
dinary dotted  half  tints. 

Luxotype. — This  process  aims  at  the 
production  of  "grained"  negatives  by  a 
treatment  with  powdered  glass  or  other 
finely  divided  material.  It  is  very  new, 
and  is  not  made  public.  Its  inventors 
claim  that  it  is  photo  typographic,  and 
that  they  can  produce  blocks  very  cheaply, 
from  which  good  impressions  can  be 
taken  in  the  ordinary  printing  press 
working  with  great  rapidity.  I  saw 
several  prints  in  a  journal  of  photog- 
raphy. They  were  printed  on  text-paper, 
and  had  the  appearance  of  very  delicately 
executed  wood  cuts. 


122 


Beproduction  of  Polychromes.  — We 
have  thus  far  been  interested  only  in 
processes  for  the  reproduction  of  mono- 
chromes. The  great  and  constantly  in- 
creasing demand  for  copies  of  the  many 
beautiful  paintings  old  and  new,  true  in 
color  and  in  chiaro-oscuro ;  the  still 
greater  demands  of  the  industrial  arts 
for  high  grade  work  in  colors  are  stimu- 
lating invention  and  taxing  the  abilities 
of  men  engaged  in  this  work.  The  chro- 
mo-lithographic  processes  have  attained  a 
high  degree  of  perfection,  and  the  beauti- 
ful prints  of  Messrs.  Prang  &  Co.  on 
satin  and  on  paper  have  never  been  sur- 
passed in  tone  or  finish.  A  skillful  artist 
can  paint  on  stone  as  he  would  on  can- 
vas, but  with  this  difference,  in  working 
on  stone  he  sees  the  results  only  in  his 
imagination  and  must  wait  for  a  proof. 
In  canvas  the  immediate  results  are  in- 
cessantly under  his  eye.  The  discovery 
of  a  means  of  photographing  color  has 
been  announced  at  stated  intervals,  but 
investigation  has  revealed  the  fact  that 
the  color  has  been  introduced  in  the 


123 

printing,  and  was  not  found  in  tli£ 
tive.  Many  years  \mve  been  devoted 
efforts  to  obtam  a  plate  from  which 
number  of  colors  can  be  printed  by  a 
single  pressure.  The  process  of  steno- 
chromie  promises  a  great  deal,  but  for 
some  unknown  reason  it  has  not  entirely 
succeeded.  It  is  briefly  as  follows  :  Pieces 
of  color  for  each  tint  on  the  drawing  ars 
carefully  adjusted  to  their  places  on  paper, 
so  as  to  constitute  a  mosaic  tracing  in 
paint  on  the  paper.  The  unsized  paper 
which  is  to  receive  the  print  is  impreg- 
nated with  the  essence  of  turpentine ;  it 
is  then  pressed  on  the  colors,  and  a  su- 
perficial dissolution  of  them  takes  place, 
and  the  paper  is  removed  carrying  tin  im- 
print of  the  colors  which  constituted  the 
stenochromic  block.  It  is  thought  that 
the  expense  attending  it  has  prevented 
its  adoption. 

The  Bonnaudtype  process  for  coloring 
photographs  is  used  in  New  York  to  some 
extent,  and  is  as  follows  :  A  feeble  proof 
of  the  negative  is  taken,  so  as  to  have 
an  indication  of  the  various  places  occu- 


124 


pied  by  the  colors.  When  the  colors 
have  been  applied  a  very  light  impres- 
sion is  taken  on  sensitized  paper,  a  very 
light  image  is  developed  on  this,  and  is 
fixed  and  washed  as  usual,  and  after  dry- 
ing it  is  immersed  for  2  or  3  seconds  in 
rectified  alcohol.  When  this  liquid  has 
evaporated  the  proof  is  run  through  the 
press  for  polishing.  It  is  then  colored 
with  a  brush,  using  vegetable  colors. 
After  the  coloring  is  terminated  it  is 
again  passed  through  the  polishing  press ; 
it  is  than  immersed  in  rectified  alcohol, 
and  lastly  the  surface  is  albuminized. 

An  inking  apparatus  has  been  invented 
by  J.  L.  F.  Eice,  of  Cambridge,  Mass., 
which  can  be  attached  to  our  ordinary 
printing  press,  and  any  desired  number 
of  colors  can  be  printed  at  one  impres- 
sion, but  only  in  bands  or  stripes. 

Conclusion.  —  I  have  endeavored  to 
give  brief  outlines  of  the  various  proc- 
esses of  reproduction  in  use  to-day.  It 
will  be  readily  seen  that  constant  study 
by  a  large  number  of  inventors  and 
scientific  men  has  resulted  in  a  series  of 


125 

processes  and  patents  so  nur 
so  closely  allied,  that  it  is  d3 
classify  them.  Many  of  the  patents  have 
fallen  into  the  public  domain,  and  have 
been  rendered  of  practical  rise  in  in- 
dustry. The  details  of  others  are  strictly 
guarded  secrets.  They  are  all  beyond 
the  reach  of  amateurs,  and  require  much 
skill  and  knowledge  in  the  operations. 
Advantages  are  claimed  for  each  process, 
and  excellent  specimens  of  each  can  be 
shown.  We  are  principally  interested  in 
the  reproduction  of  maps  and  of  mechan- 
ical and  architectural  drawings  ;  sensitive 
papers,  the  hextograph  and  photography 
are  within  our  reach.  Experiments  with 
any  of  the  other  processes  would  result 
in  many  signal  failures.  For  contract 
work,  requiring  rapidity,  economy  and 
excellence,  we  have  nothing  better  than 
the  various  processes  of  lithography. 
We  have  many  good  lithographing  es- 
tablishments. Prices  are  moderate,  and 
the  work  excellent.  Combined  with 
chromo -lithography  and  photo-lithog- 
raphy it  is  very  wide  in  range.  Thousands 


126 


of  copies  can  be  obtained  from  one 
lithographic  transfer.  One  establishment 
at  Berlin  produced  500,000  maps  during 
war  of  1870-71. 

For  the  selection  of  a  method  for  the 
reproduction  of  any  work,  we  must  be 
guided  by  three  things,  viz.,  the  cost,  the 
rapidity  with  which  the  work  can  be  ex- 
ecuted, and  its  durability.  The  proc- 
esses are  sufficiently  numerous,  and  are 
rich  enough  in  results  to  meet  any  de- 
sired requirements.  They  are  daily 
reaching  higher  grades  of  development, 
and  beautiful  pictures  are  being  brought 
within  the  reach  of  all  classes.  The  ten- 
dency of  the  day  is  undoubtedly  towards 
the  invention  and  perfection  of  typo- 
raphic  processes,  but  I  Ihink  that  I  am 
safe  in  saying  that  a  typographic 
block  can  never  be  made  to  give  the 
beauty  and  brilliancy  and  the  pureness  of 
line  obtained  from  engraved  plates.  This 
is  clearly  illustrated  in  the  two  processes 
for  the  production  of  heliogravures. 
Many  skilled  men  are  engaged  in  the  re- 
production of  artistic  works,  and  it  is  to 


127 


their  genius  and  artistic  taste  that  we 
owe  our  homage  for  the  many  beautiful 
things  brought  within  our  reach  and 
made  available  for  home  decorations,  for 
by  delicacy  of  handling,  and  quick  ap- 
preciation of  the  possibilities  in  chem- 
istry, light  and  mechanics,  they  have 
made  the  latter  subservient  to  the  artis- 
tic tastes  of  mankind. 


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and  Projectiles,  with  Practical  Suggestions  for  their  Im- 
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nance,  U.  S.  A.  36  plates.  4to,  cloth..'.   6  00 


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C  a  I  :\T  {Prof.  WM .)    A  Practical  Treatise  on  Voussoir  and  Solid 

and  Braced  Arches.   i6mo,  cloth  extra  $i  75 

CALDWELL  (Prof.  GEO.  C.)  and  BRENEMAN  (Prof.  A.  A.) 
Manual  of  Introductory  Chemical  Practice,  for  the  use  of 


Students  in  Colleges  and  Normal  and  High  Schools.  Third 
edicion,  revised  and  corrected.  8vo,  cloth,  illustrated.  New 
and  enlarged  coition.    .    I  50 

CAMPIN  (FRANCIS).   On  the  Construction  of  Iron  Roofs.  8vo, 

with  plates,  cloth     2  00 

CHAUVENET  (Prof.  W.)  New  method  of  correcting  Lunar 
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rate  of  a  chronometer,  by  equal  altitudes.    8vo,  cloth  200 

CHURCH  (JOHN  A.)    Notes  of  a  Metallurgical  Journey  in 

Europe.    8vo,  cloth  2  00 


CLARK  (D.  KINNEAR,  C.E.)  Fuel:  Its  Combustion  and 
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W.  Williams;  and  the  Economy  of  Fuel,  by  T.  S.  Pri- 


deaux.  With  extensive  additions  on  recent  practice  in  the 
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 A  Manual  of  Rules,  Tables,  and  Data  for  Mechanical 

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Half  morocco  10  00 

CLARK  (Lt.  LEWIS,  U.  S.  N  )  Theoretical  Navigation  and 
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cloth   1  50 

CLARKE  (T.  C.)  Description  of  the  Iron  Railway  Bridge  over 
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CLEVENGER  (S.  R.)  A  Treatise  on  the  Method  of  Govern- 
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COFFIN  (Prof.  J.  H.  C  )  Navigation  and  Nautical  Astrono- 
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COLBURN  (ZERAH).    The  Gas-Works  of  London.  i2tno, 

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COLLINS  (J  AS.  E.)   The  Private  Book  of  Useful  Alloys  and 

Memoranda  for  Goldsmiths,  Jewellers^  etc.   i8mo,  cloth.. .  50 


4 


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CORNWALL  (Prof.  H.  B.)  Manual  of  Blow  Pipe  Analysis, 
Qualitative  and  Quantitative,  with  a  Complete  System  of 
Descriptive  Mineralogy.  8vo,  cloth,  with  many  illustra- 
tions.   N.  Y.,  1882  $2  50 

CRAIG  (B.F.)  Weights  and  Measures.  An  account  of  the 
Decimal  System,  with  Tables  of  Conversion  for  Commer- 
cial and  Scientific  Uses.    Square  32m©,  limp  cloth   50 

CRAIG  (Prof.  THOS.)    Elements  of  the  Mathematical  Theory 

of  Fluid  Motion.    i6mo,  cloth     I  25 

DAVIS  (C.  B.)  and  RAE  (F.  B.)  Hand-Book  of  Electrical  Dia- 
grams and  Connections.  Illustrated  with  32  full-page  illus- 
trations.   Second  edition.    Oblong  8vo,  cloth  extra   200 

DIEDRICH  (JOHN).  The  Theory  of  Strains  :  a  Compendium 
for  the  Calculation  and  Construction  of  Bridges,  Roofs,  and 
Cranes.  Illustrated  by  numerous  plates  and  diagrams. 
8vo,  cloth   5  00 


DIXON  (D.  B.)  The  Machinist's  and  Steam-Engineer's  Prac- 
tical Calculator.  A  Compilation  of  useful  Rules,  and  Prob- 
lems Arithmetically  Solved,  together  with  General  Informa- 
tion applicable  to  Shop-Tools,  Mill-Gearing,  Pulleys  and 
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DODD  (GEO.)  Dictionary  of  Manufactures,  Mining,  Ma- 
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DOUGLASS  (Prof.  S.  H.)  and  PRESCOTT  (Prof.  A.  B.)  Qual- 
itative Chemical  Analysis.  A  Guide  in  the  Practical  Study 
of  Chemistry,  and  in  the  Work  of  Analysis.  Third  edition. 
8vo,  cloth   3  50 

DUBOIS  (A.  J.)  The  New  Method  of  Graphical  Statics.  With 

60  illustrations.   8vo,  cloth   1  ^o 

EASSIE  (P.  B.)  Wood  and  its  Uses.  A  Hand-Book  for  the  use 
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EDDY  (Prof.  H.  T.)  Researches  in  Graphical  Statics,  embrac- 
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Stress  in  Graphical  Statics.   8vo,  cloth   1  50 

ELIOT  (Prof.  C.  W.)  and  STORER  (Prof.  F.  H.)  A  Compen- 
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Nichols.    Illustrated.    i2mo,  cloth   1  50 

ELLIOT  (Maj.  GEO.  H.,  U.  S.  E.)  European  Light-House 
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5 


ENGINEERING  FACTS  AND  FIGURES.  An  Annual 
Register  of  Progress  in  Mechanical  Engineering  and  Con- 
struction for  the  y«ars  1863-64-65-66-67-68.  Fully  illus- 
trated. 6  vols.  i8mu,  cloth  (each  volume  sold  separately), 
per  vol  $2  50 

FANNING  (J.  T.)  A  Practical  Treatise  of  Water-Supply  En- 
gineering. Relating  to  the  Hydrology,  Hydrodynamics,  and 
Practical  Construction  of  Water-Works  in  North  America. 
Third  edition.  With  numerous  tables  and  180  illustra- 
tions.  650  pages.    8vo,  cloth   500 

FISKE  (BRADLEY  A.,  U.S.  N.)    Electricity  in  Theory  and 

Practice.   8vo,  cloth   2  50 

FOSTER  (Gen.  J.  G.,  U-  S.  A  )  Submarine  Blasting  in  Boston 
Harbor,  Massachusetts  Removal  of  Tower  and  Ccrwin 
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FOYE  (Prof.  J.  C.)  Chemical  Problems.  With  brief  State- 
ments of  the  Principles  involved.  Second  edition,  revised 
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FRANCIS  (JAS.  B.,  C  E.)  Lowell  Hydraulic  Experiments: 
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on  the  Flow  of  Water  over  Weirs,  in  Open  Canals  of  Uni- 
form Rectangular  Section,  and  through  submerged  Orifices 
and  diverging  Tubes.  Made  at  Lowell,  Massachusetts. 
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periments, and  illustrated  with  twenty-three  copperplate 
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FREE-KAND  DRAWING.  A  Guide  to  Ornamental  Figure 
and  Landscape  Drawing.  By  an  Art  Student,  i8mo, 
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GILLMORE  (Gen.  Q.  A.)  Treatise  on  Limes,  Hydraulic  Ce- 
ments, and  Mortars.  Papers  on  Practical  Engineering,  U. 
S.  Engineer  Department,  No.  9,  containing  Reports  of 
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  Practical  Treatise  on  the  Construction  of  Roads,  Streets, 

and  Pavements.    With  70  illustrations.    i2mo,  cloth   2  00 

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GOODEVE  (T.  M.)   A  Text-Book  on  the  Steam-Engine.  143 

illustrations.    Kir.o,  cloth  2  00 

GORDON  (J.  E.  H.)  Four  Lectures  on  Static  Induction.  i2mo, 

cloth     So 


6  D.  VAN  NOSTRAND'S  PUBLICATIONS. 


GRUNER  (M.  L.)  The  Manufacture  of  Steel.  Translated 
from  the  French,  by  Lenox  Smith,  w  ith  an  appendix  on  the 
Bessemer  process  in  the  United  States,  by  the  translator. 
Illustrated.    8vo,  cloth  $3  50 


HALF-HOURS  WITH  MODERN  SCIENTISTS.  Lectures 
and  Essays.  By  Professors  Huxley,  Barker,  Stirling,  Cope, 
Tyndall,  Wallace,  Roscoe,  Huggins,  Lockyer,  Young, 
Mayer,  and  Reed.  Being  the  University  Series  bound  up. 
With  a  general  introduction  by  Noah  Porter,  President  of 
Yale  College.    2  vols.  i2mo,  cloth,  illustrated     2  so 

HAMILTON  (W.  G.)  Useful  Information  for  Railway  Men. 
Sixth  edition,  revised  and  enlarged.  562  pages,  pocket  form. 
Morocco,  gilt  2  00 

HARRISON  (W.  B.)  The  Mechanic's  Tool  Book,  with  Prac- 
tical Rules  and  Suggestions  for  Use  of  Machinists,  Iron- 
Workers,  and  others.  Illustrated  with  44  engravings. 
i2mo,  cloth   1  50 

HASKINS  (C.  H.)  The  Galvanometer  and  its  Uses.  A  Man- 
ual for  Electricians  and  Students.  Second  edition.  i2mo, 
morocco   1  50 

HENRICI  (OLAUS).  Skeleton  Structures,  especially  in  their 
application  to  the  Building  of  Steel  and  Iron  Bridges.  With 
folding  plates  and  diagrams.   8vo,  cloth   1  50 

HEWSON  (WM.)  Principles  and  Practice  of  Embanking 
Lands  from  River  Floods,  as  applied  to  the  Levees  of  the 
Mississippi.   8vo,  cloth   2  00 


HOLLEY  (ALEX.  L.)  ATreatiseon  Ordnance  and  Armor,  em- 
bracing descriptions,  discussions,  and  professional  opinions 
concerning  the  materials,  fabrication,  requirements,  capa- 
bilities, and  endurance  of  European  and  American  Guns, 
for  Naval,  Sea-Coast,  and  Iron-Clad  Warfare,  and  their 
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948  pages,  493  engravings,  and  147  Tables  of  Results,  etc. 
8vo,  half  roan    10  00 

 —  Railway  Practice.  American  and  European  Railway- 
Practice  in  the  economical  Generation  of  Steam,  including 
the  Materials  and  Construction  of  Coal-burning  Boilers, 
Combustion,  the  Variable  Blast,  Vaporization,  Circulation, 
Superheating,  Supplying  and  Heating  Feed-ws.ter,  etc., 
and  the  Adaptation  of  Wood  and  Coke-burning  Engines  to 
Coal-burning  ;  and  in  Permanent  Way,  including  Road-bed, 
Sleepers,  Rails,  Joint-fastenings,  Street  Railways,  etc.,  etc. 
With  77  lithographed  plates.   Folio,  cloth  12  00 

HOWARD  (C.  R.)  Earthwork  Mensuration  on  the  Basis  of 
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D.  VAN  NOSTRAND'S  PUBLICATIONS. 


from  End  Areas.  Illustrated  by  Examples,  and  accom- 
panied by  Plain  Rules  for  Practical  Uses.  Illustrated.  8vo, 
cloth  $1  50 

INDUCTION-COILS.  How  Made  and  How  Used.  63  illus- 
trations.   i6mo,  boards    50 

ISHERWOOD  (B.  F.)  Engineering  Precedents  for  Steam  Ma- 
chinery. Arranged  in  the  most  practical  and  useful  manner 
for  Engineers,  With  illustrations-  Two  volumes  in  one. 
8vo,  cloth   2  50 

JANNETTAZ  (EDWARD).  A  Guide  to  the  Determination  of 
Rocks:  being  an  Introduction  to  Lithology.  Translated 
from  the  French  by  G.  W.  Plympton,  Professor  of  Physical 
Science  at  Brooklyn  Polytechnic  Institute.    i2mo,  cloth         1  50 

JEFFERS  (Capt.  W.  N.,  U.  S.  N.)  Nautical  Surveying.  Illus- 
trated with  9  copperplates  and  31  wood-cut  illustrations. 
8vo,  cloth  ,   5  00 

JONES  (H.  CHAPMAN).  Text-Book  of  Experimental  Or- 
ganic Chemistry  for  Students.    i8mo,  cloth  . .    1  00 

JOYNSON  (F.  H.)    The  Metals  used  in  Construction:  Iron, 

Steel,  Bessemer  Metal,  etc.,  etc.    Illustrated.  i2mo,  cloth.  75 

  Designing  and  Construction  of  Machine  Gearing.  Illus- 
trated.  8vo,  cloth   2  00 

KANSAS  CITY  BRIDGE  (THE).  With  an  account  of  the 
Regimen  of  the  Missouri  River,  and  a  description  of  the 
methods  used  for  Founding  in  that  River.  By  O.  Chanute, 
Chief-Engineer,  and  George  Morrison,  Assistant-Engineer. 
Illustrated  with  five  lithographic  views  and  twelve  plates  of 
plans.   4to,  cloth  6  00 

KING  (W.  H.)  Lessons  and  Practical  Notes  on  Steam,  the 
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gineers, Students,  and  others.  Revised  by  Chief-Engineer 
J.  W.  King,  U.  S.  Navy.  Nineteenth  edition,  enlarged. 
8vo,  cloth  2  00 

KIRKWOOD  (JAS.  P.)  Report  on  the  Filtration  of  River 
Waters  for  the  supply  of  Cities,  as  practised  in  Europe, 
made  to  the  Board  of  Water  Commissioners  of  the  City  of 
St.  Louis.  Illustrated  by  30  double-plate  engravings.  4to, 
cloth    15  00 

LARRABEE  (C.  S.)  Cipher  and  Secret  Letter  and  Telegra- 
phic Code,  with  Hogg's  Improvements.  The  most  perfect 
secret  code  ever  invented  or  discovered.  Impossible  to  read 
without  the  key.    i8mo,  cloth   I  00 

LOCK  (C.  G.),  WIGNER  (G.  W),  and  HARLAND  (R.  H.) 
Sunrar  Growing  and  Kefining.  Treatise  on  the  Culture  of 
Sugar-Yielding  Plants,  and  the  Manufacture  and  Refining  of 
Cane,  Beet,  and  other  sugars.   8vo,  cloth,  illustrated  12  oo 


8 


D.  VAN  NOSTRAND'S  PUBLICATIONS. 


LOCKWOOD  (THOS.  D.)  Electricity,  Magnetism,  and  Elec- 
tro-Telegraphy. A  Practical  Guide  for  Students,  Operators, 
and  Inspectors.   8vo,  cloth.. .   .  .  §2  50 

LORING  (A.  E.)  A  Hand-Book  on  the  Electro-Magnetic  Tele- 
graph.   Paper  boards   o  50 

Cloth   75 

Morocco   I  00 

MacCORD  (Prof.  C.  W  )  A  Practical  Treatise  on  the  Slide- 
Valve  by  Eccentrics,  examining  by  methods  the  action  of 
the  Eccentric  upon  the  Slide-Valve,  and  explaining  the  prac- 
tical processes  of  laying  out  the  movements,  adapting  the 
valve  for  its  various  duties  in  the  steam-engine.  Second  edi- 
tion.   Hlustrated.    4to,  cloth   2  50 

McCULLOCH  (Prof.  R.  S.)  Elementary  Treatise  on  the  Me- 
chanical Theory  of  Heat,  and  its  application  to  Air  and 
Steam  Engines.   8vo,  cloth   3  50 

MERRILL  (Col.  WM.  E.,  U.  S.  A.)  Iron  Truss  Fridges  for 
Railroads.  The  method  of  calculating  strains  in  Trusses, 
with  a  careful  comparison  of  the  most  prominent  Trusses,  in 
reference  to  economy  in  combination,  etc.,  etc.  Illustrated, 
4to,  cloth     5  00 

MICHAELIS  (Capt.  O.  E.,  U.  S.  A.)  The  Le  Boulenge 
Chronograph,  with  three  lithograph  folding  plates  of  illus- 
trations.  4to,  cloth  300 

MICHIE  (Prof.  P.  S.)  Elements  ot  Wave  Motion  relating  to 
Sound  and  Light.  Text-Hook  for  the  U.S.  Military  Acade- 
my.   8vo,  cloth,  illustrated. . .   5  00 

MINIFIE  (WM.)  _  Mechanical  Drawing.  A  Text-Rook  of  Geo- 
metrical Drawing  for  the  use  of  Mechanics  and  Schools,  in 
which  the  Definitions  and  Rules  of  Geometry  are  familiarly 
explained  ;  the  Practical  Problems  are  arranged,  from  the 
most  simple  to  the  more  complex,  and  in  their  description 
technicalities  are  avoided  as  much  as  possible.  With  illus- 
trations for  Drawing  Plans,  Sections,  and  Elevations  of 
Railways  and  Machinery  ?  an  Introduction  to  Isometrica? 
Drawing,  and  an  Essayon  Linear  Perspective  and  Shadows. 
Illustrated  with  over  200  diagrams  engraved  on  steei.  Ninth 
edition.   With  an  Appendix  on  the  Theory  and  Application 

of  Colors.   8vo,  cloth      4  00 

u  It  is  the  best  work  on  Drawing  that  we  have  ever  seen,  and  is 
especially  a  text-book  of  Geometrical  Drawing  for  the  use  of  Me- 
chanics and  Schools.  No  young  Mechanic,  such  as  a  Machinist,, 
Engineer,  Cabinet-maker,  Millwright,  or  Carpenter,  should  be  with- 
out it." — Scientific  American. 

  Geometrical  Drawing.    Abridered  from  the  octavo  edi- 

N   tion,  for  the  use  of  schools.    Illustrated  with  forty-eight 
steel  plates.   Fifth  edition,   iamo* cloth.  2.  00 


D.  VAN  NOSTRAND'S  PUBLICATIONS.  9 


MODERN  METEOROLOGY.  A  Series  of  Six  Lectures,  de- 
livered under  the  auspices  of  the  Meteorological  Society 
in  1878.    Illustrated.    i2mo,  cloth  $1  50 

MORRIS  (E.)  Easy  Rules  for  the  Measurement  of  Earth- 
works, by  Means  of  the  Prismoidal  Formula.  78  illustra- 
tions.  8vo,  cloth   1  5° 

MOTT  (H.  A.,  Jr.)  A  Practical  Treatise  on  Chemistry  (Quali- 
tative and  Quantitative  Analysis),  Stoichiometry,  Blow-pipe 
Analysis,  Mineralogy,  Assaving,  Pharmaceutical^  Prepara- 
tions, Human  Secretions,  Specific  Gravities,  Weights  and 
Measures,  etc.,  etc.,  etc.  New  edition,  1883.  650  pages. 
8vo,  cloth    4  00 

NAQUET  (A.)  Legal  Chemistry.  A  Guide  to  the  Detection  of 
Poisons,  Falsification  of  Writings,  Adulteration  of  Alimen- 
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and  examination  of  Hair,  Coins,  Arms,  and  Stains,  as  ap- 
plied to  Chemical  Jurisprudence,  for  the  use  of  Chemists, 
Physicians,  Lawyers,  Pharmacists,  and  Experts.  Translat- 
ed, with  additions,  including  a  list  of  books  and  Memoirs  on 
Toxicology,  etc.,  from  the  French.  By  J.  P.  Battershall, 
Ph.D.,  with  a  preface  by  C.  F.  Chandler,  Ph.D.,  M.D., 
LL.D.    i2mo,  cloth  2  00 

NOBLE  (W.H.)    Useful  Tables.    Pocket  form,  cloth   so 

NUGENT  (E.)  Treatise  on  Optics  ;  or,  Light  and  Sight,  theo- 
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PEIRCE  (B.)    System  of  Analytic  Mechanics.    4to,  cloth  10  00 

PLANE  TABLE  (THE).  Its  Uses  in  Topographical  Survey- 
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"  This  work  gives  a  description  of  the  Plane  Table  employed  at 

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PLATTNER.  Manual  of  Qualitative  and  Quantitative  An- 
alysis with  the  Blow-Pipe.  From  the  last  German  edition, 
revised  and  enlarged.  By  Prof.  Th.  Richter,  of  the  Roval 
Saxon  Mining  Academy.  Translated  by  Prof  H.  B.  Corn- 
wall, assisted  by  John  H.Caswell.  Illustrated  with  87  wood- 
cuts and  one  lithographic  plate.  Fourth  edition,  revised, 
560  pages.   8vo,  cloth   500 

PLYMPTON  (Prof.  GEO.  W.)  The  Blow-Pipe.  A  Guide  to  its 
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  The  Aneroid  Barometer:    Its  Construction  and  Use. 

Compiled  from  several  sources.  i6mo,  boards,  illustrated,  50 
Morocco   1  00 


10  D.  VAN  NOSTRAND'S  PUBLICATIONS. 


PLYMPTON  (Prof.  GEO.  W.)  The  Star-Finder,  or  Plani- 
sphere, with  Movable  Horizon.  Printed  in  colors  on  fine 
card-board,  and  in  accordance  with  Proctor's  Star  Atlas. .  .$roo 

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No.  27.— ON  BOILER  INCRUSTATION  AND 
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r  M.  P.  E.  Berthelot. 

rice. 

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